AUG 12 2008 Update
Constant Speed Prop
EagleTree Data/Movies
Old 2G Drive on Cap
Warbird Survey!!

Merry Christmas, Happy Holidays, and Happy New Year.

Another short update. 

Looks like there is some progress being made for our prop design, just not as fast as I would like.

As the year closes, I am preparing to go to upgrade school in mid January and have to buckle down and study more that play with cool props. Once I am in school, I will be focused on that activity until end of February. I may get to do some prop work or not, we'll just have to see how that goes (I spend several weeks in Dallas so can't do much prop work there).

On a completely different note I have been spending the last few weeks with my mom who is in poor health and 88 years old.  She had an emergency trip to the hospital last week, made it home and she is now on Hospice care.  She is one tough old bird, but it's a matter of time, and not much time at that.  So, for those of you who are wondering if I will ever answer my emails, yes, I will, but right now I am focusing on family and not much more.

I hope to put things in order by early spring to get these props done, or stop the project. I'm rooting for finishing things. 

On that note, I wish you all a safe, healthy and happy New Year.

November 15, 2007

have been remiss in continuing to update the website, so here is the long over due update:

Over the last 4 months my business associate has been deep into a special project that has totally consumed all of his time, and then some.  It's a pretty exciting project that we cannot talk about, but it is not hobby related.

What this has meant is that there has been very little work on the new Constant Speed Prop Hub or blade design.  I know that is not what you all want to hear but it is what is happening with our drive and prop.

So, what will that mean for all of us that want to fly a Scale, Constant Speed propeller on our Warbirds?

It means that we are pretty much where we were when I broke the prop prototype on the test stand.

I know that we have created a lot of interest and due to our delays, have probably lost some enthusiasts along the way.  We have probably even lost of some of our die hard fans.  Believe me, it is not our intent to make you all (and me too!) frustrated in getting our Constant Speed propeller out there for people to fly, but all of these delays have been unforeseen.

What I can tell you is that we are still interested in providing this type of technology to our hobby friends and enthusiasts. We think that its cool and will make your warbird really look scale and perform extremely well.

So, what's next.  It's up to us to figure out if we can get this done in a reasonable period of time or decide to turn off the website and do this all behind the scenes, and when it is done then come back and see if you all are still interested. 

We do not have a current timeline, but we will be more diligent in updating the site more frequently.  I guess I have been a little frustrated and didn't want to post monthly updates with no new information. 

So, if you are still interested, thank you very much. If we have lost you, I'm sorry to have let you down.

Have a great Holiday Season and more updates to come

PS, I go to the "school house" in January for 1 month to upgrade, so I will be pretty busy and will not be working on this, however we will be doing some work on the project but it won't be by your's truly.

Thanks for your interest.  Shoot us some email's and we'll shoot you some answers.  

July 1, 2007

Let me be the 1st to thank all of you for your continued inquiries and supportive email while we sort thru our various projects.  It is especially gratifying as our progress (or seeming lack there of) doesn't seem to deter your interest.

We have decided to completely redesign our Constant Speed propeller hub and some of the blade design.  We have been thru multiple iterations since we first started out on this project 2 plus years ago, and we continue to learn and refine our designs.  We will incorporate some of the "lessons learned" from our multiple other projects that we are working on that are not hobby related.

We have had to juggle limited resources against these multiple projects, and unfortunately for the hobby folks, the P-51 Scale Warbird Constant Speed variable pitch propeller has had to take a back seat to the other projects in process.  While this has caused much more delay than I would like, it does allow us to incorporate those design changes that we know will make a difference in both performance as well as ease of operation, maintenance, durability and service life.

We have had a LOT of recent questions on a couple of topics that we want to share here with you.  We are requesting that you write us directly to give us the feedback on the following questions.

MARCH 5, 2007

The Latest and not so Greatest.

As of last week, we have made a decision not to attend Toledo.  It was a very difficult decision, but since we are not in a position to present a Scale Warbird Constant Speed Prop that will be available for sale, we cancelled our planned visit.

We will continue to work on out development as we know there are quite a few of you out there that are still interested in our progress.

  We regret not being able to give you a hard "on sale" date, but since it is development, it sometimes takes longer than any of us (trust me this is a HUGE understatement) would like.

February 5, 2007

Late but here it is

As was mentioned in previous website updates and emails to those who have written, we are in the middle of finishing up another project that is taking up the vast majority of our time. We are working in parallel on the Scale Constant Speed WPD P-51 Prop, but it will be slow going for a couple of months. 

We have secured a booth for Toledo 2007.  Some of you have asked will we be showing a product there for sale?  It is our intent, if we go, to have a product there to show and to take orders for it then.  Will that happen?  Lots of factors there, but never the less, we will continue to work on improvements to the Constand Speed Scale Propeller.

We have done lots of testing over the last few weeks and have made major improvements to many of the components for the WPD.  We still have more work to go. 

That's it for now, more in a few weeks.

am changing my auto email responder to say 72 hours because 48 just wasn't realistic based on many different factors.

Again, thank you all for your interest

December 5, 2006 UPDATE

Well, another month has passed and while we are making progress, we still don't have something ready for you to purchase.  More development work still needs to be done, which is a perfect seque to the next paragraph.

For quite some time now we have been working on another project. Our engineers have been focused on that project and I have been supporting that project with about 80% of my time (primarily testing) which has curtailed our progress on the Scale Constant Speed WPD P-51 Mustang Prop.

Our other project is coming to a milestone so that we should be able to make more direct, measurable and reportable progress on the WPD prop, so, to that end, I am going to continue to report here on progress but based on what we have to complete, I think that the month of December 2006 will be pretty quiet for WPD. 

We are also in the process of evaluating our attendance at the Toledo Weak Signals 2007 show. I love going, really enjoy exhibiting but also want to look at this year as a pivitol year regarding having something to sell to those who are interested in our product (yes we would take care of those of you who have indicated that they want one and put themselves 1st on the list!).  I have to decide by January 15th and will let you all know if we are going.

That's it.  No other videos, pics or "other" news.  We know that this post may kill the level of enthusiasm for the Scale Prop, but better that than the slow trickle of info.

Have a great and safe Holiday Season.

Joe Boyd

November 1, 2006 UPDATE

Finished doing more testing last week and this week.  I've been doing independant tests with the governor doing some fine tuning and are pretty pleased with the results.

I have just finished editing a video which i will upload tomorrow night. It will be quite large, but kind of fun to watch.  Click here with Post Mortem on damaged blades OUCH!! (26MB and about 3 minutes long.

What you will see in the video is what happens when you are in a huge rush and don't properly secure your teststand.  I thought that it was a test stand failure, but in fact, i just had not secured the stand properly (normally use 2 50# cement blocks oriented a particular way, didn't orient them properly this time).

I was so excited to be using my new video camera that i didn't notice the stand rocking back and forth, and, yup, you guessed it, the stand went toppling over at almost full throttle, approx 2600 prop RPM and slammed into my brick patio face first. Like I said, its kind of a fun video to watch (in a sort of sick way).

Today's update is a place holder for a longer update and that video file upload tomorrow.

This little excursion will put us back a few weeks at the least. It will also give us a reason to make the changes we have been putting off to blades, hubs, actuating rods, etc.

Oh well, back to the drawing board!!

We really appreciate your support and interest. Its getting cold here in Chicago but we still will be conducting tests with the goal of flight test again soon and the all important on sale date in the future.

We're also going to upgrade the website as I am getting kind of tired at looking at this the way it is.

We're also going to upgrade the website as I am getting kind of tired at looking at this the way it is.

Thanks for your interest and support

Joe Boyd

October 3, 2006 UPDATE

I have been having problems with my ISP for the last few days which is why this update is a little late.

We are still working on the redesign of the prop blades, hub and actuating mechanism.  We have made some progress, but not as much as we would like.  There will be an update later in the month, and here is a link to the video we told you about.  There is an overshoot (intended) and then governing at prop RPM of 2600..  Hope you find it interesting, and it is edited down so that it is downloadable. CLICK HERE

That's it for this update. Hope to have more later. 

Again, thanks for your interest and support

Joe Boyd

September 1, 2006 UPDATE

Well, we survived August pretty much intact, except for my right index and middle finger. 

While breaking in a new motor, I was checking the muffler output so as to not spray my wife's plants with break-in oil, and I got a little too close to the prop for my own good.

While I was still able to get some motor data, I did have to stop after the rag I wrapped around my fingers got a little soaked, well, you get the picture.  Only 5 stitches in the index finger, and my finger is almost back to normal.

While I was still able to get some motor data, I did have to stop after the rag I wrapped around my fingers got a little soaked, well, you get the picture.  Only 5 stitches in the index finger, and my finger is almost back to normal

So, now on with the news.

We have made a significant change to the internal blade bearings, and the results are very good, reducing the wear to almost nothing, removing backlash, and making a more sturdy assembly.

We have done pretty extensive work on the governor, and it's doing what we need and expect it to do. 

We are going to make a pretty radical redesign of the prop shanks and part of the actuating mechanism, as well as the linkage.  While than means a delay, and that is not great news, it is better than sending out something that will not be up to your expectations and our need to deliver a safe, robust product

We have made a decision not to sell the Drive separately from the Prop and Governor (some of you have asked for this).  The rational behind not selling the Drive separately is that since we are going to change the prop assembly, we are going to, most likely, make changes to the Drive. If we make changes to the Drive, there is no guarantee that the new Drive will be backwards compatible with the new Drive, so a Drive at this time has very questionable value

.We are still doing testing, will still do some flight test, and are still planning on selling the Scale Constant Speed Prop (I have a Comp-Arf Mustang that is almost ready for a complete setup so I do have some pretty strong motivation). More of an update later in the month, and I will post a small video (very small) of the drive running and keeping the speed of the prop constant.

August 1, 2006 UPDATE

This will be another short update on the progress on our Scale Constant Speed Propeller System.

We have done additional static testing since the July 1st update.  The last update chronicled the problems with the flight test, which we have overcome on our static test rig.

Static testing continued successfully during July, but did show some unacceptable wear on the blade shanks. The fix maybe fairly straight forward, or pretty radical, and will be based in part on the post mortem which is scheduled for today, in about 1 hour from when this is being posted.

We expect that the teardown will show us what parts need to be either beefed up, or completely redesigned.  Since we have heavily modified the rotating parts from the original design, there is only so much more that can be changed before we have to make new rotating components.  If we have to make new components because we can no longer modify the parts we have, then we have to consider either quickly making the same parts and then remodifying them (not a very efficient way of doing it), or incorporating the changes in a redesign of the original parts. If it is the former, that means a shorter time till next test, if we have to do a complete redesign on the blade or actuating mechanism, then that will be a longer time period.   

We did get in 12 test runs and got valuable data on the electronics end of things.  The electronics are doing what we need them to do, so that means that we have some mechanical gremlins to sort out.  

We have received  a request to purchase just the drive unit without the hub, and we are evaluating that right now.  I expect that we will have an answer on that here in the next few days.

August is a busy month for us.  I have some personal stuff (like ground school and a check ride mid month) and some government stuff that I have to finish, along with an additional project, all due at the end of the month.  Nevertheless, we will continue to post here the latest successes and the not so successful results of this development project.

Once again, thank you for your patience, interest and support.

Joe Boyd


Latest News

We continued to do our testing this month, and had a setback on June 16th.  We had done some ground tests of one of the versions of the 4 Blade Prop (the one that flew in March) and were satisfied that things were ok.  Note to self, better preflight please.

On the 16th, our test pilot and I prepared to do a series of flights (several club members were there to watch-typical right, you only have problems when there are lots of people around).

We got a solid 8000 RPM on the ground (motor RPM) but I did notice that our telemetry was showing excessive cylinder head temps.  I should have believed the telemetry. 

We went ahead and started the takeoff roll, only to have very poor acceleration.  Instead of aborting the takeoff, Brian got it airborne and struggled around the 1st climbing turn about about 30 MPH-thank goodness for huge, forgiving wings!   Brian made several racetrack patterns, where we never got the RPM above approximately 9000 RPM, but we also never got the airspeed above about 48 MPH.  Something was seriously wrong, as the last time we flew the plane easily flew at 80 MPH and even hit 90+ (albeit at high RPM).  The cylinder head temp was approaching 324 F, clearly not where we wanted it to be.  Rather than risk the airframe any further, Brian made a precautionary landing.  He treated it as a deadstick, since I was convinced that this motor had been abused enough that it might quit at any time.

Running it on the ground really didn't help much, and the CHT's were barely decreasing at all. We did show full prop actuation.  Here is what the post-mortem showed.

As I mentioned up above, we have several different versions of the blade/hub design.  While this one had flown successfully before, it had been highly modified and treated pretty roughly, overstress and oversped, and did have some components that were less than optimal, but ok for testing purposes.  Well, an internal component failed, and we in effect had one blade creating negative thrust.  That aerodynamic unbalance created contact between the large pulley (aluminum) and the flywheel (steel) in only one location.  This incidentally transmitted a tremendous amount of heat to the prop hub mechanism.  (just a useful bit of forensic information).  The intermittent contact between the flywheel and driven pulley was what caused the CHT's to be so elevated-in effect, I had a DA powered lathe!  Ouch is right. 

The good news is that we have another design (quite a bit different internally) for the hub and blade, which we will be testing this month.  We are also going to make some changes to the actuating mechanism, because we are not happy with some of the wear characteristics.

What does this mean.  Well, as you can imagine, it means that nothing for sale here soon.  Sorry to disappoint. I have struggled with the idea of going dark on all this stuff relative to the development of our Constant Speed Propeller because it's not clear to me if you want this type of info or not. We get quite a few inquiries about purchasing a system (as well as "can you adapt this for XXXX motor/plane/size prop/number of blades) and we hate to keep saying, "not yet". 

If you think that getting this type of information is of value, let us know. If you think that it is worthless, we can go dark for a few months and then give you a big update.  Your choice, I think that I am too close to the situation to not be biased.

So, have a great 4th, more info to come (probably mid to end of the month) and thanks for your continued interest.


I am one day late and I can tell you, unless you NEED surgery on your sinus', don't even think about it.  I am really apologizing for being tardy but I am having OK days and pretty awful days. Today is an in between day, and I got over 4 hours of sleep for the 1st time since last Friday.  Flying into a level 5 TS would be easier!!

Enough of me, what about WPD.

We are continuing to do more of the same.  Refining design. testing bearings, making some system changes, trying to get things done so you can buy a few drives.  I should be able to resume some flight tests mid month, and as I am not allowed back at work until July 5th at the earliest, that gives me some time to recuperate and fly. My test pilot, Brian Johnson, has agreed to more flying and since it will not be 30° F outside, it will be more conducive to testing.

Update on flying will be coming up by mid month.  I hope to post some of the EagleTreeSystems FDR files online so those of you that have one can download the files and look at the data.

I know that some of you are probably pretty frustrated that we aren't done yet.  I understand the feeling.  Sometimes I feel like giving birth to an elephant - with a 3 year gestation period.  I WANT to be done.  We will get it done.

Thanks again for your continued interest and support.

Joe Boyd

MAY 22, 2006 UPDATE

Was Toledo Really Almost 2 Months Ago??

 I just realized that my quickie update of late April was not the update that I promised on May 5th, so, with apologies, here goes, the official WPD Constant Speed Scale Propeller UPDATE.

The Good News

We had a great show at Toledo, and lots of serious interest in our Constant Speed Scale Warbird Propeller.  We got to see some of our old friends, make quite a few new ones, and make a favorable impression on a few people who are interested in us doing something with TurboProps, among other proposals.  

We are interested in all these new opportunities but we know our first mission is to get things done for you folks who have been so patiently waiting for us to finish our product and get some out in the field.  (We did talk with a professional video team who wants to shoot some video for us to show you -- 5 cameras, including In-Aircraft!) It was a successful show, and we’re looking forward to 07

The Other News 

We have been working on this project now for over 2 years, and I hate to say it but we are still “almost” done.  Fortunately, we do see light at the end of the tunnel, and it’s not a freight train!  We have a few issues that still need to be resolved including design changes that, while small, take a tremendous amount of time – resolving the issue, creating new drawings, fabricating the part, testing it, and making whatever subsequent fixes rear-up as results of this one.  

The issues aren’t “show stoppers” but they relate to making sure that when we are done and ready to go into serial manufacture, the 1st blade will look like the 1000th blade.  We also have to ensure the ability to easily manufacture a large number of blades and drives that will not be so labor-intensive we cannot meet price and delivery expectations.  

So, while we’re just as eager to predict the “on sale” date as you are to read it, these next changes keep us from doing this.  It’s pretty much the nature of R&D, not to mention inventions that are self-funded and handled only when one is done with one’s day job.  However, since we have had successful flight tests, and will continue to do more flight and static testing in June, our goal is to have the design “frozen” by late summer

The Outlook

We will continue to make the necessary before-market design changes that will insure the product you buy will be high performance, safe and reliable.  And we’ll continue to do our flight testing and share the results with you.  On a personal note, there will be a few blackout dates in early June while I recuperate from some imminent sinus surgery but on the bright side, at least I’ll have a month off from my “day” flying job so I can time to getting this project that much closer to successful completion.

We can’t tell you how much we appreciate your patience and we hope you are still as excited by the Constant Speed Scale Warbird Propeller as we are.    

Thanks for your continued support.  

Joe Boyd


ts been a great show at Toledo, the response is pretty amazing.  Thanks to everyone for stopping by.  Here is a picture (I'll take a better one tomorrow) from the show.  Lynn, send me a better photo!!


This is a short one, because we are packed up and headed for TOLEDO!!!  BOOTH 90

We'll be showing off our Drive, Constant Speed Prop and will have 2 drives there, one mounted in a Mustang, the other on a display stand for you to get up close and personal with.  We'll also have a movie of the CS Prop flying the plane below.

So, please stop by Booth 90 and say hello. We're looking forward to talking RC planes and flying, and of course, Big Scale Constant Speed Props!!  See you there!!

MARCH 11, 2006 UPDATE  don't forget to look at the bottom to see Super Pilot Brian!!

We are finally getting around to posting an update on what we have been up to.  We’ve flown the Constant Speed prop on the big Super Flyin King. Just to recap its specs:  132” W/S, 94” Long, 26” wing chord, 3380 sq. inches of wing area, 35# weight. Test flight date was March 4, 2006. Here is a link to that 1st flight MOVIE.  Its HUGE at 45 MB.  Don't even think about downloading it unless you have a high speed connection.

This massive testbed was brilliantly flown by our friend Brian Johnson of Venture Hobbies, Wheeling Illinois.  It was 42°F with 8mph of wind.  We were using our trusty DA-50R swinging the 26” 4 blade (2” chord) Hamilton Standard prop. 
NOTE: This is our "stock" picture and doesn't show the Scale Prop. Have to look at the movie for that. We will fix that in by end of July 06.

This massive testbed was brilliantly flown by our friend Brian Johnson of Venture Hobbies, Wheeling Illinois.  It was 42°F with 8mph of wind.  We were using our trusty DA-50R swinging the 26” 4 blade (2” chord) Hamilton Standard prop. 

The prop was set so that the low (or fine) pitch was 16°, or about 18.75” of pitch.  This was done so that in the event of a failure of the pitch servo, pitch servo battery (we are running a separate battery) or pitch control linkage, the minimum pitch available would be enough to fly the airplane.

To prove that theory, we did our takeoffs with minimum pitch selected, 16° of pitch.  The airplane accelerated briskly and was airborne in about 80 feet. Brian could have pulled it off the ground sooner, but he was being extra cautious.  And good thing too, because right at takeoff, the right aileron servo arm left the servo along with the aileron linkage (Brian knew right away). I found out about this AFTER the plane landed. I think Brian was trying to spare me the stress of losing ½ of the aileron control.

We saw speeds of 67 MPH at 8000 RPM; this was with the prop still in flat pitch.  (we lost the telemetry early on, so this is from looking at the data on the ground-telemetry loss my fault, it was set on low power).

These 1st flights were not using the governor function, as we wanted to fly the plane with low pitch (16°) to simulate having no prop control. Top speed was 77 MPH at 9300 RPM (Prop RPM 3576).  Not bad for a 50 cc motor on a 35# plane

Flight # 1 was cut short due to error #2 for the day, which was my fault. I was concerned about CG and after some discussion, elected to only fill the fuel tank about ½ way.  Or, so I thought.  This is a 40oz. tank, and in retrospect, I probably put in about 8 oz of fuel.  So, after the multiple starts, runups, and taxi out, and flying at high throttle settings, we had the dreaded DEADSTICK, engine out landing.  

There is a reason that we have Brian signed up as the test pilot. Besides being a great pilot, and a good friend, nothing fazes him.  Not losing 1 aileron on takeoff, or having a deadstick going downwind at 100 feet with a 35 # airplane that he only has 3 flights on.  My only contribution was to move the pitch to coarse (or max pitch-somewhere around 40°) to reduce drag.  The prop stopped and only turned about 2 revolutions after the motor stopped.  The blades weren’t feathered, but pretty close (at least as close as we could get them).

After reattaching the aileron, and checking the fuel system, we decided to COMPLETELY fill the fuel tank and try again.

This time we did a ½ flap takeoff (Super Flyin King folks, you know what I’m talking about) and the plane leapt off the ground in about 40 feet.  Flight number 2 was much less eventful.  Everything stayed attached, we flew it for about 8 minutes including a landing and another takeoff.  We again didn’t use the governor and attained a max speed of 90 MPH @  Motor RPM 10,563 and Prop RPM of 4063. No, we don’t recommend running at that RPM, EVER. 

The good news about running at that high RPM is that we got some of the stress testing of the prop out of the way, by exceeding the prop RPM by 35%.  Everything looks just great, no damage to any components including the DA 50.  

Next flights should happen just before Toledo and should be utilizing governor mode.  We will post a movie download link on the main page and have a nicely edited movie for Toledo.  

Our thanks to camera man David Tietel and test pilot Brian Johnson for taking some time out of their weekend and days off to fly and film. 

Next update in about 2 weeks.

March 04 2006 UPDATE

We are going to do something a little different this month for updates.  We will be posting at least 1 more this month, after the flight of the Constant Speed Prop on the new testbed aircraft.  We might even have 2 or 3 updates, so, stay tuned. 

This is going to be a very short update.  What's new is that we have made some additional enhancements to the blades, prop hub and other subsystems of the Constant Speed Scale Propeller.  It will make it more robust, increase longevity and also make it easier to manufacture.

The other news is that we have made our first flight of our new test aircraft, a Bruce Tharpe Super Flyin King.  This is a 132" Wingspan, 94" long 27 # (flight weight without engine) high wing workhorse.  We were lucky to get this from a gentleman who had done an outstanding job building it, and so for us, the timing was just right to acquire the plane. 

It has a 28" wing chord, semi symmetrical wing.  3350 sq. inches of wing area!!!  Can you say "light wing loading!!"  Our good friend, Brian Johnson was the test pilot.  The plane will fly so slow with flaps deployed you can just about jog faster than it flies.

A picture of the plane is below.  With our calibration flights with this plane out of the way, we will now unbolt the DA 100 motor that we flew it with and mount the Reduction Drive, Constant speed prop, and then go fly.  We were going to fly it this weekend (March 4-5th) but the weather here in Chicago doesn't look very favorable, so the 1st flight may be the following weekend.

A picture of the plane is below.  With our calibration flights with this plane out of the way, we will now unbolt the DA 100 motor that we flew it with and mount the Reduction Drive, Constant speed prop, and then go fly.  We were going to fly it this weekend (March 4-5th) but the weather here in Chicago doesn't look very favorable, so the 1st flight may be the following weekend.

We are still planning on being at Toledo on April 6-8. Don't know if we will have a system for you to take home with you, but we are pulling out all of the stops to get to a point where we can take orders at the show.  Keep your fingers crossed!

And as always, thanks for your continued interest


February 2006 UPDATE

Well, good and bad news to report.

1st, the good news.

On January 14th, we did are actual 1st test flight of the Constant Speed Prop. It was a success!!! It flies, it governs, it works!!!  This was the very same setup that you see in the new pictures that we posted here.  Aircraft was a Hanger 9 1/3 Scale Cap 232, weighing in at 30#.

We had been working diligently over the previous 4 days reworking internal hub mechanisms, tweaking blades, making several modifications to both the blades and hub, and doing numerous ground runs in between all of the changes.

Off to the flying field where it was sunny, windy and 54°F.  After doing some more ground running, it was time to fly.  This is a text description as the video is not good enough to post.

The ground was covered with about 1” of crunchy ice, so the plane was a little hard to taxi. In order to keep the plane from nosing over because of the ground covered in ice (and the plane breaking thru like a mini-icebreaker while taxiing); I had the elevator on high rates - 45°.  (1st mistake) 

We could see the governor doing its thing, and although the takeoff roll was a little sluggish, it was horsed into the air after I made the decision to takeoff and not investigate the slow takeoff roll (2nd mistake).

Even thought I took off at too low an airspeed, the plane started to accelerate pretty quickly once free of the ground, and we could hear the governor governing.   I made a turn to start a downwind parallel to the runway and the plane started to descend pretty rapidly (nose heavy, forward CG?)  So, I pulled up to level which was immediately followed by a rapid right roll.  

Why?  I absolutely don’t know.  The prop was running fine, the telemetry from the EagleTreeSystems DFDR shows that the plane was rapidly accelerating, the prop servo was not drawing too much amperage and was governing, so I feel confident that I had plenty of airspeed, but I was plagued with a rapid right roll and a nose down condition that was getting the best of me.  

Also, I remained on high rates on the elevator. (3rd mistake)  Why?  Probably too much adrenalin.  I knew I should have switched to low rates, but I was concentrating on why the plane was rolling right so rapidly.  Oops!

Well, you can probably guess the bad news……   On the 3rd right roll, I corrected and then I just rolled over hard to the right and kinda acted like a lazy snap into the ground. (Should have powered back??  (4th mistake)

According to the Flight Data Recorder, level flight speed was 73 MPH and at impact (recording cutoff – 84 MPH). 

Based on the post crash investigation, what we found out was that the prop was making power, the governor was governing, and all of the onboard prop control systems were working as advertised.   When we got the radio and servos back from Horizon, what as found were 2 stripped servos on the control surfaces (left inboard aileron, right elevator), the throttle servo was stripped, and the right rudder servo was completely burned out, both the motor and the pot.

I could blame the radio, but I really cannot say with any confidence that it was contributory to the crash.  Nope, I didn’t get “hit”.  Yes, I might have gotten behind the airplane and introduced a Pilot Induced Oscillation (PIO) and simply rolled left and pulled back too hard the 3rd time as the airplane keep accelerating and caused the lazy snap into the dirt.  One thing for sure, it made a pretty big scar in the ground!!!
The good news was that the prop hub, blade fork, spiderblock, fork control rod were all completely undamaged.  So, we got the “crash damage tolerance test” out of the way!!  The frame for the actual drive was bent and is trash.  The pulleys are serviceable.  The blades, unfortunately, did break.

We would have posted all of this sooner, but we have been concentrating on finding a replacement test bed, making some new components and making some final design changes.  

We have a new test bed aircraft, a Bruce Tharp Super Flyin King.  This HUGE airplane is going to be perfect for our needs.  Its 132” Wing Span and 90” long.  Giant Flaps and 7” wheels!!  It’s supposed to weigh in at about 36 # with a DA 100 on it, so it will be about 37# when we are ready to go.  Haven’t actually weighed it yet, will try and get that done tomorrow.

We have about one month to do some more flight test so that we can be comfortable with the design and freeze it, complete our endurance testing on our ground test rig, and see if we can get some units produced in time for Toledo.  That’s the goal.

Our thanks to all you folks out there that are watching us toil away.  It’s encouraging, especially when you have some setbacks.  

We may have time to share some updates with you during February. If we do, you’ll see them posted here.

Thanks for your continued interest.

JANUARY 2006 Update

This is the update for January 2006, just posted a little bit earlier than I had planned.

Well, finally, we have had successful runs of our new design blades in the Constant Speed Propeller hub.  These are the new design Scale Mustang P-51 blades, and they are magnificent if I do say so myself.  More on that later, here is the test info.

It was 42 degrees and sunny when we did the test, 68% humidity, baro 30.14”

After getting the fuel to the DA 50R motor, and having it pop a few times on choke, it ROARED into life and I had no throttle control since I programmed it thru the Throttle Jockey to command low throttle on start. Which, of course, didn’t work at all since the throttle servo was reversed in throw.  No fault of the TJ, just a dumb (mine) programming error.

So, the good news is that the prop, all 4 blades of it, can actually run at 6°of pitch at 4800 prop RPM.  Since the drive ratio is 2.6:1, that meant that the motor RPM was 12,480 RPM.  OUCH!!! Seems like I have done this before with the with another prop setup.  

Now, just to be clear, we do not endorse running either our prop at 4800 RPM or the

DA 50R at 12,480 RPM. even for a second.  I let this run for about 90 seconds (mostly because I was wary of walking past those blades whirling around so much faster than our design RPM).  I’ll be a little modest here and say our blades stayed together and didn’t show anything worse for wear.  The DA 50R was just fine too.

We shut down the motor by cutting the ignition, and then, not wanting to try and trouble shoot where the problem was (TJ or operator error-and again, it was operator error) we elected to connect the prop control servo directly to the receiver and the motor throttle directly to the receiver (this is when we discovered that the throttle servo was reversed).  We only had about 1 hour to run the test so we didn’t have time to reconnect the TJ after the 1st and 2nd runs. 

What followed were 2 separate runs, one of 16 minutes, another 7 minutes long.  We ran the prop at RPM ranges from 1300 to 3500 prop RPM, and pitch from 6° to 45°.  We started to explore specific RPM/pitch combo’s so we could look at vibration issues to see what changes we might need.  We also were looking for reactionless mode vibrations. 

We really ran this motor very hard, with lots of high pitch settings, and the drive frame, bolts, and importantly, the belt showed no signs of wear or vibration issues.  The temps of the motor were fairly consistent, and only got higher when we stopped the motor suddenly after a high RPM, high pitch run. While the motor was running, the temps were in the 130-210°F range. After shutdown, they did go higher (after the high power run) but there was no cooling airflow over the motor (the prop blast doesn’t really do much on the test stand, and DA expressly advises you not to run the DA-50R on a test stand for any length of time without cooling fans directing airflow over the cylinder. The base of the motor stayed over 40 degrees cooler then the head.  Not sure which is more important here?

By the way, the prop blast was ENORMOUS when the pitch was increased to 45°.  I had a set of hearing protectors on over my baseball cap and it was blowing the darn things off my head. I know, not like a thrust reading, but that is coming.

You can find a VERY LARGE video of the test run here (45MB, no kidding).  The quality of the film is fair.  I had to shoot it in a very short time period.  I really needed 3 hands but only had 2!!  I’ll be getting a real video camera here soon, so the vids will be higher quality and smaller.

So, what’s next?  More ground running, fine tuning the TJ setup, then flight test.  With my schedule for January, it will probably be the 3rd week of January before of flight test.  

As for the blades.  With the new hub design we can get the blades to do just what we want them to do.  They are super strong, light (hollow) and are exhibiting good vibration characteristics. What had started out to be a minor set of changes turned out to be a complete rethinking about how to actuate the blade itself, and the result is greater strength as well as what we believe will be more longevity.  The finish is just about perfect, as these are only test and not production blades.   

We have made our booth reservations for Toledo, and will be there with a couple of drives mounted in a few planes, and with some luck, a few for you to handle (and……)

Until the next month or big update, thanks for your continued interest.



Joe Boyd

December 1st, 2005 UPDATE

The latest news from Warbirdpropdrives.com is that we have had several successful ground runs of the Constant Speed prop!!    We THINK that we have solved most of the big issues an a lot of the smaller ones, and now are getting prepared to do some endurance ground testing to make sure that everything holds together before we do our first flight test.  

The ground runs have been made with a non-flight worthy propeller, and so we have almost finished making a set of flight worthy blades that incorporate all of the changes necessitated by the ground tests.  

The changes were pretty small in most cases, but there were a few major changes which will involve changing the spider block and parts of the blade root, but the good news is that this new design will be much more robust to increase reliability and longevity.

I’ll be able to post some new pics of the new blades (sorry, no pics of the inner workings of the hub).  Video of the ground test to follow.

Since it is winter here in the Midwest, and my December schedule is such that I get Friday’s off (Saturday’s and Sunday’s as well) I’ll be doing flight test as the weather and schedule permits.  

More updates within the month of December.

November 1st, 2005 UPDATE

Well, it’s only been a few weeks since our last update, but we have been making steady progress.  This will be a short update as we should have some more info within the monthly update cycle which will be posted here.

We have completed a redesign of our Constant Speed Hub, and incorporated features that will make the design more robust and allow for longer blade and hub life (we were not satisfied with the previous designs wear characteristics).

This redesign has caused us to have to remake our test blades, which has pushed back the testing schedule by about 3 weeks.  The new test articles are complete, and more testing is to be completed within the next 2 weeks.

We are also working on a very exciting project that we know our IMAC friends will want to hear about, but we aren’t quite ready to post anything significant on that yet.

We realize that this is a rather short update, but until we get the performance out of our test articles, the amount of information to post here will be limited.

 We will be emailing all if we get an update to post before the 1st of the month.

 Thanks again for your renewed interest and patience

October 1st update

It's only been a few days since our last update, but we have made significant progress.

What we determined in our last tests is that we have to do another redesign of some of the internals in the blade.  This has more to do with giving the blades a resonable service life than anything else, but as you know, these changes take time.  We'll do more testing over the next few weeks, and we will report back here our results.

So, while I would like to post more, there is really nothing more to post (I don't want to go into the technical details here). 

I do promise that I will post every 1st of the month.  We are getting close, but we're not there yet.

Thanks for your continued interest and patience.

September 19th UPDATE

As a fan of the website pointed out, I had promised to update the website regularly on the 1st of each month.

Well, I screwed up and didn’t do it!!   Mea culpa!

I have been waiting for the last changes to be finished and then I wanted to update the site with some new pictures and video to show you we haven’t been asleep these last few months.  

That was the plan.  The reality is, we haven’t progressed as quickly as we had projected.  That’s the bad news.

The good news is we have solved so many of the problems that have been, to put it mildly, vexing us.  

These include, but aren’t limited to

Mold release not releasing (solved)

Above problem damaging mould (solved after a lots of “surgery” to the mould, perhaps 20 hours of work just here

Parting line (solved)

Changed lay up schedule (solved) 

Internal workings of the blade (cant talk about that, but solved), 

Blade surface finish (solved) 

Shank changes (solved) indexing pin retention (solved) .

Each “solved” takes days or longer, and that’s why this is taking the time it is taking.  

We remain committed to making this work, and while I cannot predict when we will have it all solved, it is getting done.  We haven’t gone out of business, and we will continue to develop this for the RC hobby community.

Now, the next update WILL be on the 1st, even if it is….no further info.

So, thanks again for understanding part of what we are going thru.

July 1st 2005 UPDATE

Well, time for an update as to what is happening at WPD

1st, thanks for all of your interest and perseverance regarding our Constant Speed Prop and Reduction Drive systems.  There is considerable interest, not only from hobbyists, but from some other folks (you can use your imagination), so we must be on to something.  Now, as to what is happening.

In a nutshell, development work is taking longer than we had expected and anticipated, and in my personal impatience of trying to make people happy, we got too optimistic in our projections.  My partner, who has much more experience in development work than I do, suggested that I not be so aggressive in our schedule, but hey, I’m a hard headed pilot and an optimist, so, I thought that we could still achieve our schedule; we would just have to work “harder”.

One of the issues that I am finally beginning to “get” is that it might take us 2 weeks to work thru a design change and manufacture a set of blades, and then, during testing, we destroy a couple of blades in 30 seconds.  Add to that cycle 2 or 3 times, and now you can see what we have been experiencing.  Previously, we have done the testing in a separate location from the manufacture of the blades, which has necessitated a back and forth shipping time delay, coupled with troubleshooting the “problem” or failure mode long distance.

So, one of our process changes we have instituted is to perform some of the early development testing at the manufacturing location.  That should streamline the early testing process, and get us to a flight test sooner than our previous method.  

For those of your with a technical orientation, the area we are working on involves the manufacturing process of the blades.  We have some issues, but no show stoppers.  We aren’t trying to defy the laws of physics, but we are doing something that is unique and patentable, so it is taking longer (or the right amount of time-depending if you are taking to me or my partner!!) than we would like, and we know its taking longer than YOU would like.

We’ll get it done, but we have decided that I should temporarily retire from the prediction business as to when we are going to have something to post on the website as to “testing to be done on this date, flight test on that date, for sale date of XXX.

I cannot tell you how much we would like to take your money and ship you a system, but right now, they aren’t ready and cannot be shipped.  We have every confidence that we will create a solid, working system, but posting a date and then not hitting it just erodes our credibility and probably irritates you as well.

We also decided a long time ago, that we wouldn’t ship something to anyone that we weren’t absolutely sure of as far meeting or exceeding our safety, performance, and quality goals.  We are small, and the risk of going to market with a product that is not ready is not with the downside of creating a huge negative buzz in the marketplace that would be difficult to overcome. If we make a mistake, we won’t get a second chance with this product.  So again, as much as we would like to ship, we can’t.

This was a tough update to post, but after getting a few emails from some folks that were, quite frankly, skeptical that we were deliberately being evasive, I decided to write this.  I’m a hobbyist 1st, and a business person 2nd.  I want this to work, and have enough confidence in our product, engineers and manufacturing guys that I know it will work, but just cannot predict exactly the date. It’s closer than it was 2 months ago.  I hate waiting for hobby stuff (how about that cool Hanger 9 incidence meter/throw meter), so I think I know how you all feel.

Thanks for your interest, and please do come back to look at the website for updates. I will update monthly around the 1st of the month, regardless of if I have movies or test data to post, just so you won’t wonder were we went. 

Some folks have asked about the pricing, and we are still shooting for $ 300 USD for the drive,
$ 390 USD for the prop hub and constant speed governor, and $ 30 USD per blade.

Thanks again for your interest, support and understanding.  We’re modelers too, and want to fly this setup as much as you do!!

April 30 UPDATE

Hello All:

1st, I would like to thank you for taking the time over the last 18 months to email us with your interest in and questions about our Reduction Drive, and now our Constant Speed Prop.

I was on a Red Eye flight the other day and it struck me that you all have taken the time to write me at one time (or 2 or 3) but I haven’t written specifically to you.

So, please accept my apologies and let me tell you what is happening.

1st, Toledo was a big success. We were not only able to showcase our new Constant Speed Prop design, but also to meet new like minded RC enthusiasts, chat with old friends as well as chatting with multiple vendors, and even get some press coverage (we are supposed to be in the latest issue of FLY RC, and possibly High Flight).  Not bad for 3 days of hanging out doing what we like to do.

Now, the info that you all want to hear on the drives.


We have the drive unit itself ready to go to market after some additional testing.

We have made 3 changes now to the lay-up schedule on the prop blades, and we think we have it just where we want it. It is a balancing act between enough material for strength and stiffness, and not too much.

We are completing our vibrational testing this weekend.  This is very critical, as when the prop is running, we don’t want to have any frequencies that resonate and create extraordinary stress on the blades and set the blades up for failure.  This has to be right, or the blades will fail.


We have done some flight testing of the TF Mustang to get some performance metrics.  Almost done with these tests, just a few more flights to complete.

The H9 1/3 Scale 97” WS CAP 232 is ready for its 1st flight with the reduction drive.   This is the plane featured in the videos on the website with the old design drive.

Blades should be out of my partner’s hands and into mine by middle of next week.

If the weather holds out, I plan on some ground tests May 5th and May 6th. 

Based upon the Ground tests being successful, 1st flight tests to begin on May 6th.


If we have a successful flight test by May 6th and May 10th, and a few other things come together, we will pack up the plane, drive and blades and go down to the Joe Nall fly-in.  We may or may not fly there, but we would be there to show off the drive, blades and an installed drive in the Mustang.


Joe Boyd


Well, it's finally here.  We're at the 51st Toledo Weak Signals show, and it is really a blast!  I forgot how much fun it is to be at this place.  So, what's new?

We've made a lot of changes since the last show, but what is really new is that we has a Constant Speed prop for our Warbirdpropdrives Reduction Drive.  Really.  Now how cool is that?

We knew that last year, based on testing, it was going to be just about impossible to create a fixed pitch prop that was going to be scale, while giving you the performance that you would demand, so, we have spent the last year working on the Constant Speed design, in addition to making the changes to the actual drive that you will see below and on the next few pages.

We're going to describe what it does and why in a minute, but here is a picture of the adjustable pitch mechanism to keep your interest level high.

This is the Scale Prop hub with the front hub cover removed.  In the lower part of the picture you can see the control fork that moves the prop blade within the hub. The long rod goes thru the center of the hub and big pulley and attaches to a bellcrank. The bellcrank is actuated by a servo driven by the electronic governor.

Now it's a little more assembled. You can also get a better look at the control fork rod. 

Here the drive is installed on the TF P-51 Mustang. The cowl was sacrificed to show you that it all fits inside the cowl. (it WAS a perfectly good cowl!)  You can also see the scale exhaust from WWW.Keleo-Creations.com.  The yellow tube you see houses the cable that actuates the control arm.

The tie wrap you see on the front is holding the sensor pickup that senses the RPM of the big pulley, (tiny magnets in the back of the big pulley) and sends that info to the WWW.Modelavionics.com electronic governor.  The governor "does the math" and sends a command to move the pitch control servo to move the pitch control rod, which moves the prop blades

This is a picture of the drive and prop hub without the motor or the exhaust installed.  The side frames are made out of steel, and the round parts are made out of aluminum.  The flywheel (see above) is also made out of steel. The steel parts will be cadmium plated for corrosion resistance

Check out the next page on the website to read more about why this whole thing makes sense.

We are still moulding blades right now, and hope to have them installed here at Toledo and on this webpage by the end of the show.

This is an installation drawing with dimension data so you can what size the drive is and help you determine how it will fit in your airplane.

The custom scale muffler courtesy of http://WWW.Keleo-creations.com is done for the DA-50 Direct drive, and now Kelvin will be making us a muffler for the WPD reduction drive.

I've uploaded those http://WWW.EagleTreeSystems.com files showing performance of the old drive and prop, including the http://www.soloprops.com  3 blade SoloProp just for fun, and have also kept a few of the 2G and 3G old photos and movies, just for fun.

We were asked quite a few times what the next motor we will be making a drive for, and following successful testing of the 50 sized motors, we will be gearing up for the new DA 82(?) and the ZDZ 80.  Also in the running are the 3W motors as well as a few others. 

It takes some time to develop each sized drive, and right now we are focused on getting something out there in the field for you 1/5 scale guys, and this 50cc sized drive is intended to fit in the Top Flight P-51 ARF and kit. 

Thanks again for taking the time to visit us here.  We appreciate your interest and patience!!



Check the Photo Update page to see the drive mounted in the Top Flight P-51D!!

Special thanks to Kelvin Cubbinson of http://www.keleocreations.com  who built the custom, scale exhaust system.  It's AWESOME. Kelvin did a perfect job on this prototype of our muffler. It fit exactly in the same space as the muffler he has designed for the DA-50R direct drive setup.  Please note that I told Kelvin a measurement that was 3/8" off-my fault.  This will be corrected in the production models.

We did more test runs the other day, March 3rd.  Here are the results.

Run #3 22 minutes.  Max RPM 24" pitch was 3480. Pitts muffler, 3 strand belt ran most time at constant 3000 RPM.

Run #4 21 minutes.  Max RPM at 24" pitch was 3410.  Pitts muffler, 3 strand belt, 2600 and 3000 RPM.

Run # 5 24 minutes. Max RPM at 24" pitch was 3530.  Pitts muffler, 3 strand belt, ran most time at 3000 RPM.

Run #6 23 minutes.  Max RPM at 24" pitch was 3510.  Pitts muffler-2 strand belt. Constant 3000 RPM.


New update for February 20th.  On the 19th, we ran the new WPD reduction prop drive on the test stand.  Excellent results; the waiting paid off!!

We used the same www.Soloprop.com 3 blade adjustable pitch prop we used with the 2nd and 3rd Generation drive.  We have made a prop hub adaptor to work specifically with the Soloprop. 

1st run was 11 minutes long.  We are running a 3 strand belt for these tests, and expect to be able to go to a 2 strand belt for production on the 50cc sized motors.  With the 3-Blade, 26" X 22" pitch prop, we got 3540 prop RPM, which equates to 9204 RPM (2.6:1 ratio)

We inspected all components for any loose bolts or components. Everything looked great, so, we were ready to test again. When you run a new belt, there is a one time belt stretch, so we had to retension the belt again.  I guess i was too excited but i cranked down on a nut and snapped a bolt right off.  This was a stainless steel bolt, and yes, I know, the standard bolts are a little stronger. 

We decided to take advantage of this opportunity to run the drive with one of the motor mounting bolts gone---because we all know in real life, stuff happens!! These bolts are designed to hold the motor to the drive back frame, and also serve to allow you to put tension on the belt by pushing down on the motor and then tightening up the bolt/nut. With one of the 4 missing, we thought it would be "interesting".

Well, we ran the motor for an additional 14 minutes.  We burned a total of 32 oz of fuel thru the DA-50R at all RPM's.  The good news, even though we saw a fair amount of motor movement and belt slap during the run, the missing bolt caused no problems with the prop RPM, slippage or belt wear.  At 24" of pitch, the prop RPM was 3450 for a motor RPM of 8970. Hey, nice to take advantage of a small problem, right?  We don't ever suggest that you run your motor with a missing mounting bolt, but it was good to see that it was not a single point failure.. 

I am posting a movie, pictures of the drive and a list of reasons for some of the changes on another page. Make sure you check the index for that information.

Thanks for your patience, interest and support.  Next update March 05!!