Ken Rehler's Single Place Upgrade Pics

[CLS447]

Ken, I thought you might need a little help getting this thread going! I'll let you take it from here!!............................................ .....................

[rehler]

Chris,

I have not taken any photos yet. What I have now is so many parts in my garage that I am worried that I will forget where they all go!

I will describe what I am doing:

My Verner engine crank shaft broke - long story short, I bought a new Rotax 912S engine. After removing the old engine and looking at the gyro it became clear that now is the time to make several modifications to my gyro that I have been thinking about. Well, one thing has lead to another and now I have redesigned the entire frame, suspension, made all new parts and starting re-assembly. Following are some of the improvements I am making:

Move the horizontal stabilizer and twin rudder back 6" (longer lever arm to improve stability).

Increase legs from 17" to 20" to raise the gyro up 3" (for prop clearance after lowering the engine and prop).

Add new shock absorbers to the main landing gear.

Making all frame members out of "streamline" tubing to decrease drag.

Change the engine from the 80 hp 165 lb. Verner to the 100 hp 134 lb. Rotax 912S (less weight and more power).

Lower the thrust line 1.9" - now it will be exactly in line with the CG.

Increase the prop diameter from 65" to 67.5"

Add a muffler system - quieter.

Add a spinner to the prop - it is supposed to reduce drag even with a pusher.

Replace the 25' McCutchen rotor blades with my new 27' Sport Rotor.

When I get back in the air I should have a lighter, more powerful, quieter, more stable and more reliable single place gyro with better lift and less drag. I can't wait to fly it after all the improvements are complete.

When it is put back together I will take photos and post them.

[CLS447]

Awesome Ken, but I wouldn't mind seeing the pics of all that hard work. Maybe others could appreciate it more then! I know where you are coming from, & it don't happen overnight!!! I just can't take the suspense. C'mon , show us the nightmare! You know that you are loving it!

[PW_Plack]

Ken,

Does the gearbox on the 912 require the prop to be above the crank, as usually seen in fixed-wings, or can it be inverted to move engine-up/prop-down?

[Aussie_Paul]

Ken, there is no choice as to the redrive position on Rotax 4 strokers. You have 2 choices, prop up and prop up!!!!

Aussie Paul.

[Udi]

Replace the 25' McCutchen rotor blades with my new 27' Sport Rotor.

When I get back in the air I should have a lighter, more powerful, quieter, more stable, single place gyro with better lift and less drag...


You've forgot to mention "more reliable"... With a good fuel filter and proper maintenance this engine should never quit.

By the way, did you ever try a 25 ft. DWs? I would try them if I were you. Maybe you can find someone to loan you a set.

Udi-

[rehler]

Paul,

No, the Rotax 912 engines have the transmission as part of the engine in the up position. It can not be changed to the down position like on the 2-cycle engines.

[rehler]

Udi,

You are right. In fact, "more reliable" is why I selected the Rotax 912S engine!

I will edit my post to add it.

[GyroRon]

More performance Steven in a nut shell. Less money too and you could have them shipped probably tomorrow. They come smooth as delivered, test flown and balanced and tracked.

[CLS447]

Ken R. , Happy birthday to you! , Happy birthday to you! .

I can't wait to see your gyro, I hope all is going well !!!!!

[GyroRon]

Steve I have flown under probably over 10 sets of Dragon wings or more. They are good blades especially for the lighter machines. Sportcopters are certainly the finest blades on the market, but worth over twice the price of Dragon wings.... I don't know if I could agree.

Sportcopter is under a lot of pressure to build blades and get them out quick. They are standard on Sparrowhawks and I know a lot of the RAF drivers have put in orders etc.... I am starting to worry about workmanship on these blades. I have to call Jim or send him a email, but for some reason the blades on my friends Gyrobee - 24 foot 7 inch chord Sportcopters - have something inside one of the blades that is loose and rattling around in there. It wasn't that way when they were first put on and I haven't flapped them or hit anything with them. Maybe it is dry glue ball, a forgotten washer? Something, cause now that we discovered this sound the blades are no longer smooth like they were, the balance has gone out.

[GyroRon]

No way in the world would I wait a year for my blades no matter how good they are. And to have already paid for them.......... Oh no, that just wouldn't work. :o

You know others aren't waiting a year to get their blades from SportCopter.

[Udi]

Truth be told, I'm beginning to seriously think I should have bought a Magni M16 instead -- same price and there are no delivery problems.


Don't want to rub the salt, but you would have been better off with a Magni, for more than one reason. In my opinion the Magnis are the most refined gyros on the market. They may not be the most efficient gyros, but if it's efficiency we are after, we shouldn't fly gyroplans at all.

Udi-

[rehler]

I added some photos to my web site to show how my project is coming along. But ... they don't show much as I am just starting to assemble everything. I'll add more photos soon.

www.rvk-architects.com/ken/gyro/

Click on "New Engine 2" to see the latest photos.

[rehler]

I added new photos to my web site showing how my project is coming along.

Click on "Ken's Gyro" below, then click on "New Engine 3" to see the latest photos.

[ToddP]

Its really looking good Ken. Are you about ready for flight testing? Legally, are you required to notify the FAA about major modifications? Will they assign another "test period"?

When I applied for my airworthiness, Ernie B. recommended writing on my application that the engines was a tp101 rather than a Rotax 532. That way, even if I changed the engine it would still be a tp101. Unfotunately the FAA didn't see it quite that way and I had to change the paperwork.

[KenSandyEggo]

We're not required to notify the FAA of any major changes (provided we've upgraded our OLs). All we need do is note it in our log and fly off 5 hours in a sparsely populated area. Then log that the mods did not appreciably affect the handling characteristics of the craft. The FAA does not want to be bothered and they will not assign a new test period. If you have the old OLs and you call them, they'll tell you to upgrade your OLs......at least they should, if they're up on things, which they should all be by this time.

[Kevin_Richey]

Texan Ken:

Was enjoying your photos of your changes to your Lone Star machine...

Did you form those airfoil struts or are they available out there in the marketplace?

[rehler]

Kevin,

The streamline aluminum tubing is available from Wick's Aircraft (and others). The cross section is 1.25" by 3.125" (as I recall) and fits over a 1" x 1" tube (tight fit unless you round the corners). They also make it in a smaller size. Only problem is that you have to buy it in 10 foot sections.

I noticed LEAF has it on sale in their latest brochure.

[scottessex]

Lots of good looking work there Ken, I like it. Do you design and fabricate your own parts? If not, Your machinist deserves credit too!

Nice work!

[rehler]

Thanks Scott. Yes I do the machine work on my trusty Shop Smith (made in China).

[Dean_Dolph]

Ken, it seems to me that I came across some snap on plastic air foil sections that fit around tubing but I can't remember where I saw them. If I find time I'll look thru my favorites and see if I can find them.

[Heron]

We bought some at Sun-N-Fun and I am quoting them in Brazil (dirty cheap)
Also I've found an especial shape of aluminun profile that includes tubing and airfoil alltogether. Checking for price and temper.
Heron

[rehler]

Heron,

Do you have some of the plastic airfoil material for sale? If so, what size and how much do you want for it?

I would like to have about 3 or 4 feet of it that would fit over the 1" square tubing on my nose wheel.

[Heron]

Ken . . .sorry I do not have it yet.
The material bougth at SNF was Larry's and I do not know if he as to spare, but certainly he can direct you to the source.
I wish I could move faster but fuel is low ($$$)
Heron

[Heron]

This is the last place I've found to source materials.
Haven't got an answer yet on mimimums and such.

[Dean_Dolph]

Ken, here is the link to the plastic streamlined fairings.

http://streamline.8k.com/

[rehler]

Dean,

Thanks. The problem is - I only need 3 feet of tubing and they only sell 72 feet at a time (4 x 8' and 4 x 10').

[Dean_Dolph]

It looks like the time is ripe for someone to start a gyro co-op!

[Heron]

Gyrowave is going to help soon!
Ken call Larry Neal!
Heron

[Aussie_Paul]

Ken, the fine print is in blue. this was on the web site.PRICE: $189.95 + shipping (LARGE) and $169.95 + shipping (SMALL)

Set includes: 4 small 8' strut fairings or 4 large 10' strut fairings

Fairings are also sold by the piece...call for pricing.

---- GEAR LEG KITS AVAILABLE ----


Aussie Paul.

[rehler]

Paul,

Thanks!!

That's a major problem I have - I don't read instructions. I'll call them.

[rehler]

THE ENGINE WORKS!

I started my new 912S today for the first time and it runs smooth and quiet. Everything works - new instruments, new wiring, new low fuel warning light, oil system, water system, etc. No leaks, no problems! I'm a happy camper!! :) :) :)

But ... I tried to start it over and over again without success. You can imagine all the thoughts that went through my head. I figured I would have to start over and look at everything I did to see where I screwed up and perhaps the engine was faulty and would need to go back to the factory.

Then I thought that maybe I installed the ignition switches upside down. I know they are on to kill the engine and off to let it run, but maybe I thought too hard about it when I put them in place. Just for the heck of it I would try with the switches down. I flipped them down and pushed the started not expecting anything to happen. The engine started instantly! I installed them upside down!

Well ... almost perfect.

[Aussie_Paul]

Those little mistakes Ken make just make me feel sooooo much better.

Aussie Paul.

[ToddP]

I'm looking forward to the new flight reports Ken. It sounds like your already great machine is going to be that much better.

[GyroRon]

On my new Dominator I installed the switches so ON is down and off is up. This way if I bump the switch in flight I won't be turning it off. But it is so backwards I may flip them to be more normal

[scottessex]

I like to use a gaurded switch cover, put one on Da screw driver too. I use it in the gaurded "ON" position, can't accidently hit it.
Glad to hear you are making good progress Ken.

[rehler]

My gyro finally got back into the air Sunday afternoon ...

... and it scared the hell out of me! :eek:

As soon as I lifted off the runway it rolled sharply to the right. It felt like 45 degrees, but probably was more like 15. I gave it sharp left stick and some left pedal and let off the throttle and it then veered off to the left. Working the throttle it went up, right, down, left - all over the place. I finally left the throttle alone and flew it down to the pavement and landed, taxied off the runway, shut off the engine and sat there thinking “what just happened”?

Well I figured it out. The tremendous engine torque simply rolled the gyro to the right with power and to the left when the power was reduced. It is a really powerful engine (100 hp) for a relatively light gyro (800 pounds all up weight).

After thinking about it, what happened was the direct result of several of the changes I had made: a lot more power (increased torque), larger prop (increased torque), exact centerline thrust (no resistance to rolling about the CG, as the lever arm from the center of thrust to the CG is now zero), and I had set the pitch on the new prop to the maximum (it really “grabbed” the air).

Also, the prop now spins in the opposite direction, so my habit was to expect a slight left roll at lift off so I probable had some right stick - just opposite of what was needed with the new engine/prop.

The goal was to have a lighter, more powerful, quieter, more stable and more reliable single place gyro with better lift and less drag. I will now add “more thrilling”. I will decrease the prop pitch and try again Saturday to see if I met the other goals. There is no question that it is lighter, more powerful and quieter. :)

[MattPearson]

Your gyro looks great Ken. You could do yourself a big favor and redirect that exhaust stinger so that it's not pointing into the prop. Cuts down on noise and on some engine/redrive set-ups, there have been stress cracks caused by the power pulses inducing damaging vibrations into the prop.

[CLS447]

Congrats Ken! Which blades did you have on it?

[Udi]

Ken - Congratulations for flying your "new" configuration.

I don't think you should change the prop pitch. The engine torque is the result of engine power, not prop setting. If you want less torque, use less power! You don't have to take off with full power. Less power - less torque.

Udi-

[GyroRon]

A Tall tail would fix this Problem

[rehler]

Matt,

Thanks for the suggestion (exhaust/prop). I didn't know there was such a problem.

[rehler]

Cris,

I have the McCutchen blades on it now. After Mentone I'll have time to switch to the Sport Rotor. It requires a change in the teeter tower height and I just don't have time to do it before I leave.

[rehler]

Udi,

Less power = less torque. I guess the real problem is for me to get used to the power. Driving a 500 hp corvette is different than driving the family Buick. I need to learn how to avoid spinning the tires.

On my first (and only, so far) lift off I was nowhere near full power. It happened fast so I am not sure, but I think I was only at about 4000 rpm (5800 max). It taxies about 30 mph at idle (1800 rpm) if I don't ride the brakes. This is what makes me think the prop pitch may be too steep.

[Udi]

That engine has torque from Rev 1 and it's so easy to use it! Personally, I would set the pitch for best climb speed, not best static, since the engine has enough torque for takeoff anyway, and Ken's goal appears to be quietness and an effortless cruise.

What you are saying is true for every engine, Steven. It makes no sense to redline static, you want to redline in climb or even at a higher airspeed if you have too much power. This is not the isesue. If you have a powerful engine, guess what - you get more torque!


Udi, it's not easy to "use less power".
Actually, it is easy. You can take of with 6000 instead of 6500 RPM. What's the problem?

Udi

[Udi]

Ken - did you run the engine static? I guess I assumed that you have already adjusted the prop on the ground. If you haven't, than you may be right - the prop may have too much pitch.

Udi

[rehler]

Udi,

Now you’ve done it. You are going to make me confess.

No, I have not done a static test and I don’t have a good excuse for such poor judgement.

I reworked my hydraulic brakes when I changed my landing gear design and they now are mushy and don’t hold well. I must have air in the system. This will be my first thing to fix this weekend.

Anyway, I can only get the engine up to 3000 rpm before it starts moving forward - no matter how hard I push on the brakes. So, rather than taking the time to do it right (brace the gyro against a wall) I decided to do the prop rpm test in flight. This was a bad decision. To do my first run-up I had to check the mags at only 3000 rpm. This too was bad. Flying the gyro without ever having the engine above 3000 rpm was rather foolish.

I adjusted the prop to the maximum that the instrument that came with the prop would go. I figured I’d start there and reduce the pitch as needed to get it right. Probably should have started near the middle, but I didn’t want the new engine to over-speed.

At lease I can be an example of what not to do!

[GyroRon]

Ken just use a tie down strap to tie the gyro from the tailwheel to a tree or the trailer hitch on your truck or whatever and hop in and give the engine some throttle! No way the brakes are going to hold back that 912! the tires even locked up will just skid across the pavement. You got to tie it down and run it.

[Friendly]

yes, and don't start bragging about how you drug that truck all over the airfield with your gyro brakes own. Not everbody can afford a 912!!! lol

[GyroRon]

I was talking about the brakes and tires on the gyro not holding back that mighty 912! but I wouldn't be surprised to see it move the truck too :)

[rehler]

Ron,

I have a unique problem with my gyro - no good way to tie it down from the rear. I have no tail wheel and no center boom like most gyros. It has twin booms and rudders. If I attach to the two tail skids (about 5' apart) it puts a lot of stress on the tail booms and side frames.

You are right. I do need to ground run it. I can put the front wheel against the hangar if I tie the rotor blades so they don't swing around and hit the hangar while testing. I did this before I put the blades on when I ran the engine for the first time. That's when I should have adjusted the prop pitch.

[Udi]

I have a unique problem with my gyro - no good way to tie it down from the rear. I have no tail wheel and no enter boom like most gyros. It has twin booms and rudders. If I attach to the two tail skids (about 5' apart) it puts a lot of stress on the tail booms and side frames.

Use a load beam. See sketch:

[Dean_Dolph]

Where will it end! Ken picked up another award at Mentone. He can provide the details. I think everytime he needs a ego massage he thinks up some mod and then it is award time! Congrats!

[rehler]

Dean,

Thanks. Yes, "Grand Champion Single Place Gyroplane". And I am proud of it!

Mentone was fun - well worth the trip from Texas.

However, as luck would have it, on the way home with my brand new enclosed trailer in tow I was rear-ended! I had my cruise control on and was cruising along at 60 mph in the right lane in heavy traffic when WHAM - all of a sudden I was being pushed down the highway. After I gained control I turned on my right turn blinker and turned off at the next exit just in front of me. Stopped the car and looked around. No one was there. The cars were all driving along and there was no way I could tell who rammed me.

The read doors were crushed in and the trailer tongue was rammed into my rear bumper. I checked the gyro through the side entry door and it looked ok. There was no way I could remove the trailer from the hitch as it was inside a hole in my bumper. So, I carefully drove the rest of the way home.

Fortunately my insurance will pay for the car repair and trailer rebuild. And only one rear skid on the gyro was bent. The bent trailer doors missed my HS by about 1".

Getting everything fixed will only delay my flying a couple of weeks. Then all will be back to normal.

[CLS447]

Ken, it was great talking with you at Mentone. If I was a judge, you would have had my vote!

Sorry to hear about the hit & run, but I'm sure glad your gyro sustained little damage. That's the problem with enclosed trailers, They didn't know what they were messin with. Had it been open, you probably would've had an escort!

So lets get those trim tabs installed & get those SC blades on there. I want to see how you like them.

After reviewing my pics , I have a question for you. Why are your control rods mounted to the front of the cross tube up at the rotorhead? Does this have to do with folding the mast?

How did you escape my camera in every pic?

You sure did a great job building that beauty & you should be proud!

Don't forget to keep us all posted on the flight testing results. Maybe I can take you up in my 2 place machine next year if everything goes right. I for one am really glad you made the trek to Mentone. I hope you had as good of a time as I did. Keep up the great work!

[CLS447]

Here's a pic with your mast folded.

Do you have other towers for your SC blades?

I still think that's a 914 without the turbo! ;)

Hey everybody! Is that a sharp looking gyro or WHAT?!?

[rehler]

Chris,

Thank you. I too enjoyed talking with you at Mentone. You have a great two place gyro. Next year we can fly together.

In answer to your question, my cyclic stick was too close to my instrument panel when I pushed full forward to engage the rotor brake. So, I moved the top of the push rods forward to make the lever arm shorter, which requires less fore-aft movement of the stick. Solved my problem - expedient but a very crude way to do it.

[Udi]

Look what I found:
http://encyclopedia.thefreedictionary.com/Gyroplane

Udi-

[rehler]

Udi, now that is a great example!

It looks like the photo was taken at the EAA Southwest Regional Fly-in in New Braunfels a couple of years ago.