Changing out a 912 80 HP in a model IV

[cap01]

i just went thru the same issues with the prop flange on the new engine. luckily i had access to a newer warp hub and flange inserts. the problem was with the spinner back plate. chucked the plate in a lath and cut out the center flange hole to the correct size . i had reamed the holes in the plate for the flange inserts nuts but the plate wouldn't fit. seems all the holes had to be stretched a little to get the plate to fit. enlarged center hole was pretty much dead nuts center so that wasn't the issue. all the holes had to be stretched in the same direction so it had to be some difference between the flanges. i did find the paper work that tells about the flange changes and has the engine s/n when they changed.
at least now i have a useless old style warp hub that will probably go away when i decide what i happening to the old engine.
good luck
chuck

[Wheels]

Hey Chuck,
Seems we have twin problems. I"ll take my old plate to a machine shop I know. I don't want to wallow out the holes on the plate and rely on the center hole for alignment. I want good alignment and perfect balance.


I just don't want to change the spinner type to the crappy fiberglass style and watch it crack, flake and chip as I have seen on so many. The aerodynamic consideration is that a small spinner offers no real advantage to the flat nosed drag problem. I flew the plane without its spinner to do a prop pitch test and was amazed at the sink rate after pulling power for landing. The spinner does a great deal to enhance airflow.

My old engine is on the bench. I will sell it but haven't decided how to do that yet either. the pickup for the stator was the problem and It needs to be adjusted. The old wiring harness is just to aged to be safe in my opinion. So the core of the engine with its accessories is what I have. I"ll see who wants to play with Electrical and they will have a motor.

[cap01]

i kinda wish that i didn't have a new style hub, i had been considering getting a whirlwind for the new engine. this engine change has drug on for sooo long , i really wanted to get back to flying. i did have balance concerns for the spinner and will check it closer for center. i have ran it a couple of times and about to balance carbs and realized i have a problem with the new macfarland throttle. i have a couple of people that have shown interest in the old engine but i haven't given much thought how to deal with that . i seem to have a nagging concern about liability.
did you hook up the soft start on yours? it really works nice.
hope you sort out the spinner plate. i never realized there was a problem until i
i went to change over the insert nuts on the flange, was a big surprise.
cp

[Geowitz]

If you end up needing a new spinner that will have to be drilled anyways check out B&B Sport Aviation in Maryland. They are the KievProp dealer and sell an 8.75 Inch carbon/fiberglass spinner. Great quality and durability. No cracking or crappy gelcoat to deal with. Comes in 3 blade version, but when I switched to 2 blade they were able to sell me a dome that had not been cut and I fitted it myself. Not sure what diameter you need, but figured I'd give them a plug. I think it's about $250. Sorry, don't have a better pic right now.

https://www.bbsportaviation.com/

[Guy Buchanan]

A tip for your new spinner:


Before you put on the spinner backing plate, install #10 nutplates at about 8 or 9 locations on the vertical face near the edge, but far enough away to accomodate #10 fender washers. Set the nutplates so you can screw into them from behind the spinner and thereby attach weights (washers). This makes dynamic prop balancing much easier. You can then add weights at each nutplate without removing the prop or spinner. Super-easy.

[cap01]

good tip, thanks

[avidflyer]

Wheels, I sent you a PM. JImChuk

[jrevens]

A tip for your new spinner:


Before you put on the spinner backing plate, install #10 nutplates at about 8 or 9 locations on the vertical face near the edge, but far enough away to accomodate #10 fender washers. Set the nutplates so you can screw into them from behind the spinner and thereby attach weights (washers). This makes dynamic prop balancing much easier. You can then add weights at each nutplate without removing the prop or spinner. Super-easy.

That’s a great idea, Guy! If you started at the center line of a blade and installed a nutplate exactly every 30 deg. (12 total) it would be ideal.

[PapuaPilot]

I made 12 holes in my backplate without the nutplates. When I balanced my prop I just put the final weight in the appropriate hole.

[Wheels]

I appreciate the help. You are all awesome. I called Warp Drive and those guys have my loyalty hands down on service. Daryl spent some time on the phone with me this week and I did buy a carbon fiber spinner and back plate assembly from him. He said it was unlikely that I will need to balance the unit I am buying as it is a well designed and tested spinner. The color will match my plane and I can install and fly rather than continue the game of drilling balancing, hoping, testing, etc. Tell me no one saw this problem coming and just ignored it. Pretty much the way I feel about the last 17 minor adjustments for fitting the engine. I have not enjoyed the ride and I will NEVER build a plane. Hoping for successful engine start on Friday of next week, but I have been saying that for quite some time now. Cheers