flyrotary@lancaironline.net Mailing List Archive

I see no reason why this will not work. I'd fly it any day. I fact I'm going to fly my 20B RV-8 with 3/8" prop bolts and 5/8" drive lugs but this will be on a wood or composite FP prop. I would NOT do this on a 300 HP Lyc engine. Too much torsional vibration.

Tracy

----- Original Message -----

From: Mark R Steitle

To: Rotary motors in aircraft

Sent: Wednesday, December 15, 2004 1:35 PM

Subject: [FlyRotary] Re: M/T Prop Won't Fit PSRU

Tracy,

I had considered doing that earlier and discarded it as too simple a solution. And since I’m not an engineer, didn’t think it would be safe to fly like that. Seriously, if that is strong enough to do the job, I may give it a try. The M/T prop has a ¾ x 3/32 counterbore on five of the six holes. So, I can do this on five of the bolts. Sounds good.

Mark S.

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Tracy Crook
Sent: Wednesday, December 15, 2004 12:26 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: M/T Prop Won't Fit PSRU

Just had another idea on this.

Drill the RD-1C drive lugs to 1/2" for the sacred MT 1/2" bolts. Make a simple 3/4" OD / 5/8" ID bushing 3/32" thick and put it on one of the drive lugs.

No drilling the prop hub required.

Tracy

----- Original Message -----

From: Mark R Steitle

To: Rotary motors in aircraft

Sent: Wednesday, December 15, 2004 12:37 PM

Subject: [FlyRotary] M/T Prop Won't Fit PSRU

I have been working to resolve a problem for more than a month now and thought I would query the group for a possible solution.

If anyone else is running (or planning to run) a 3-blade M/T electric prop with the RD-2C gearbox, I have discovered a mating problem in using this prop/gearbox combination for my 20B. The problem is the RD-2C prop flange comes with 3/8 id x 5/8 od bushings. The M/T prop has a stepped hole that is ¾” for the first 3/32” and then goes to 5/8”. Tracy is not comfortable with drilling out the 5/8” bushings and M/T adamantly advises against using anything less than ½” prop bolts with this prop. So, I’m at a standstill until I can get this resolved. The only solution I can see is to press out the existing bushings and open up the holes to accept ¾” od x ½” id bushings. But that would require disassembly of the gearbox and some precision machine work, possible but not my first choice.

Mark S.

Lancair ES – 20B

(with a very pricey lawn ornament)