Here is the new procedure for removing the drive from the adapter plate:
1) remove drive and adapter plate from engine.
2) remove long bolts completely
3) smack adapter plate with a mallet - comes right off.
Here are some pictures. The plate was pretty badly broken up and was only being held together by your aluminium plate and the steel bolt ring. Pin in sun gear was also broken. No apparent serious damage, just what I assume is cosmetic galling of the input shaft, adapter plate, and bell housing from the loose pin floating around.
That is the same flex plate I have used for all 600 hrs. It has come on and off several times and I have never noticed any cracks. Now that I as able to look closer, it is clear that the flex plate was not rotating ture, but had a detectable wobble. Thinking back, I had an early sign of it at the Reno Pylon School. After one of the races I noticed that my home made cover over the flywheel had been marred by the flywheel but was not in contact with it. I attributed it to the high air speeds (205 Kts Indicated coming down "The Chute") somehow pushing my cover down onto the flywheel. I put some creases into the cover to make it stiffer which seemed to solve the problem, but perhaps the flex plate had broken at that time. With a mis-tracking flex plate it is easy to see that sun gear pins would be undergoing additional stress. So I am calling the underlying cause of both issues the flex plate failure.
The large washers that covers the rubber dampers between the dampers and the flex plate have made a significant groove into the aluminum of the attachment plate. I have never noticed that before, possibly was a function of the twisting flex plate. Question is, does it need to be replaced?
My rubber dampers are noticeably worn and soft and need to be replaced. I am getting quite a significant amount of oil coming past either my rear oil seal or the oil seal on the gear drive. That oil may have done in the rubber dampers, that got too sloppy and stressed the flex plate that eventually fatigued and broke, which further lead to the pin failure.
So I am undecided on what to do about the flex plate replacement. I agree that the iorn flywheel is not the answer. The machine work would have to be quite extensive, because the aluminum plate rides inside the ring. After all that machining, it would have to be re-balanced but that would be difficult because it has the rear counter weight built in.
Using one of the aftermarket aluminum flywheels might work. It would still have to be machined to make space for the damper plate, but at least it would be aluminum (easy to machine) and could then be balanced symmetrically (perhaps even with the damper plate installed so it is all nicely balanced. That would not be a low cost solution, however!
I am also wondering if I have any business trying to make that much HP. I was about to install a water/methanol injection system to be able to use more boost at Reno. But it seems I may not be able to safely use the HP that I already have...
--
David Leonard
Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.nethttp://RotaryRoster.net
On Tue, Jul 12, 2011 at 12:07 PM, Tracy
<rwstracy@gmail.com> wrote:
Other than the added 20+ pounds it should work fine. But I would want to know the exact mode and reason the flex plate failed. I have a collection of them that had cracks around the mounting holes at the counterweight when I received them from the salvage yard. It is possible yours was bad from the start.
20 additional pounds is a deal killer for me.
Any news on the drive failure?
Tracy,
What say you about using the heavy manual transmission flywheel if I can get it milled and fitting?
-
David Leonard
Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.netOn Tue, Jul 12, 2011 at 5:31 AM, Tracy
<rwstracy@gmail.com> wrote:
I don't think Hylomar is a sealant and would not recommend it for use on the RD-1x drive. Current instructions for the drive describe a recommended procedure for separating the drive from adapter plate. It also helps to put a light coat of oil and wipe off excess before assembly of the drive to adapter plate.
Tracy
Sent from my iPad
Ask Tracy about using Hylomar as a sealant.
Brian Trubee
-----Original Message-----
From: David Leonard <
wdleonard@gmail.com>
To: Rotary motors in aircraft <
flyrotary@lancaironline.net>
Sent: Mon, Jul 11, 2011 10:15 pm
Subject: [FlyRotary] Re: Fwd: RD-1B failure
I tried to get into the gear box today, but ran into an impasse trying to get the bell housing off the adapter plate... I think I am done using RTV there. Will probably use a non-adhesive sealant - as long as Tracy says we don't need the adhesion from the RTV.
I did find another issue. In addition to a likely fin failure inside the gear box, the flex plate is coming apart. I found a piece of it in my cowl and it is tearing in several places. Still seems to be tracking OK.
You know, I wouldn't mind the weight penalty of using the manual flywheel. Would have to drill some holes to attach Tracy's torque plate, but it should otherwise be an improvement for idle and pulse dampening. But maybe gyroscopic loads would be unacceptably high? Maybe have to move and/or replace the starter.
Will try to get some pictures tomorrow.
--
David Leonard
Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net
On Mon, Jul 11, 2011 at 11:51 AM, Mark Steitle
<msteitle@gmail.com> wrote:
Al,
My gearbox failure was approx. 1-1/2 years ago. I attributed the failure to a very rough running engine which was cured with a mod to the EC-2 and CAS. I was lucky that it happened on the ground. (Ed can keep his "King of Dead Stick Landings" plaque, thank you!)
If I am correct, Tracy installed a 3/8" pin in my input shaft. No failures since. I now have approx. 200 hours on the engine/gearbox.
Mark
On Mon, Jul 11, 2011 at 10:23 AM, David Leonard
<wdleonard@gmail.com> wrote:
From:
Al Gietzen <ALVentures@cox.net>
Date: Mon, Jul 11, 2011 at 8:17 AM
Subject: RD-1B failure
To: Dave Leonard <
wdleonard@gmail.com>
Hi; Dave,
I’m very thankful to hear that this occurred after landing.
I’ve been unable to post on the rotary engine list for months due to blocking by Cox. Perhaps you’d post this message on my behalf:
---The shear pin on the sun gear is the most likely candidate since it was sized for a normally aspirated 13B. After the failure on Marks 20B, I have changed the pin diameter
Tracy;
Doesn’t this suggest that all 20B and 13B turbo should be upgraded to the larger pin? When was the failure on Mark’s 20B?
Al
---
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