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Bob,
There are a few units that are supposed to be designed for HYD/CS. The Geared Drives unit. This is designed for it from the start. the drive incorporates a clutch and it pretty costly. 8K+! This unit is a chain drive reduction and has a sagnifigant thrust line offset. Marcotte shows the drawings for one but I have not seen it. They use a v-belt to drive a pump and governor and run a separate closed system using ATF for prop control. Cheaper at list price than the geared drives unit, (a lot in fact) But I have had trouble contacting Ray Fiset Marcottes contact with the outside world and don't know their current status. The Marcotte unit is a well made internal helical gear drive. This unit has a slight offset, about 2". Lastly Mistral, who are certifing the rotary! yea! They will sell the drive for around 7K and I think that is the bargain of the group. They have a beautifully made planetary, custom built from the ground up and really nice. They are rotary from the start too. They are certifing their G300 (300 HP 20B based) and G190 (190-200 hp 13B based). I say based because for certification they are doing their own engine parts for the required paper trail. They announced on ACRE that the 13B unit is consistant at 200 HP and that 300 HP has been no problem for the 20B based unit. Both of those engines are normally aspirated, and they will release turbo units later. They use their planetary unit on both engines. None of their stuff is cheap but it is beautifully made and works well. They have several hundred hours on their engines in a Piper Arrow and thousands of hours of dyno run time.
Ok I have run on here a bit, but I was wondering, didn't you have one of Tracys RD1-C already?
Bill Jepson
2 Apr 2008 1:35 pm
Subject: [FlyRotary] Re: Prop selection
Thanks, that helps narrow my selection. I think MT is off my list.
-----Original Message-----
From: Mark Steitle < msteitle@gmail.com>
To: Rotary motors in aircraft < flyrotary@lancaironline.net>
Sent: Wed, 2 Apr 2008 3:22 pm
Subject: [FlyRotary] Re: Prop selection
Bob,
Since I was using Tracy's redrive, the only options I had was fixed or electric (ground adjustable or C/S). I had heard about a group buy that was being put together for the M/T prop, so I jumped on the bandwagon and went with the M/T electric. M/T will paint the prop whatever color you choose. Jim Ayers was the M/T dealer that I went through.
Keep in mind that the threaded inserts that Tracy uses are a different size than what M/T uses and he won't do a special run for the M/T guys; says it is too costly to make changes to the production run. I understood his point, but that still didn't help solve my problem. So, if you go the M/T route, plan on purchasing a set of M/T bushings and having your prop flange re-machined to accept the new bushings. These are press-fit bushings, so the hole diameter is very tight tolerance for a non-standard size hole, requiring a custom ground reamer ($100). Tracy says we don't need the larger bolts, but M/T emphatically disagrees. I went the safe route and installed the M/T bushings.
If you had gone with the Marcotte redrive, you could use a hydraulic c/s prop, but the c/l of the prop shaft is different than with Tracy's, so if you haven't planned for that, now would be a bad time to change over.
Mark
On 4/2/08, bmears9413@aol.com <bmears9413@aol.com> wrote:
Mark,
When you made your prop choice, was hydraulic even an option with the 20-B setup? If it was why did you choose the electric? I keep looking at the Vesta, the veriProp, the whirlwind, and MT. Part of what I'm looking for is the WWII look also. Otherwise I would probably go with the Ivo Prop. Any feed back on these props by anyone would be appreciated.
Bob Mears
Supermarine Spirfire
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