Quantcast

Race 84 is Back!

HomeBuiltAirplanes.com

Help Support HomeBuiltAirplanes.com:

slociviccoupe

Well-Known Member
Joined
Apr 1, 2011
Messages
316
Location
Palm Bay Fl.
Too bad marcote drives no longer available. Next contender is the spg-5 gearbox as plenty of gyrocopters flying with them.
Few others out there but not a whole lot on them. Marcote was about only one with the internal helical gear.
 

aeromomentum

Well-Known Member
Joined
Jan 28, 2014
Messages
131
Location
Stuart, FL USA
We (aeromomentum.com) make a gearbox with a 9 3/4" offset that is designed for 325hp on a 4 cylinder, 425hp on a 6 cylinder and 550hp on an 8 cylinder. This is based on a peak impulse torque of 1100 ft-lbs and with an additional 2 to 1 safety factor.
 

TXFlyGuy

Well-Known Member
Joined
Apr 25, 2012
Messages
1,964
Location
Republic of Texas
We (aeromomentum.com) make a gearbox with a 9 3/4" offset that is designed for 325hp on a 4 cylinder, 425hp on a 6 cylinder and 550hp on an 8 cylinder. This is based on a peak impulse torque of 1100 ft-lbs and with an additional 2 to 1 safety factor.
Will it fit an LS3 V8? Constant speed hydraulic prop? Weight?
 

slociviccoupe

Well-Known Member
Joined
Apr 1, 2011
Messages
316
Location
Palm Bay Fl.
We (aeromomentum.com) make a gearbox with a 9 3/4" offset that is designed for 325hp on a 4 cylinder, 425hp on a 6 cylinder and 550hp on an 8 cylinder. This is based on a peak impulse torque of 1100 ft-lbs and with an additional 2 to 1 safety factor.
Nice you are advertising but do you have weight, and any real flight testing and recorded hours on them. Has one actually been on a subaru and torsional vibration rpms recorded?
Seems everyone can build a gearbox and advertise. Its not a one size fits all.
 

aeromomentum

Well-Known Member
Joined
Jan 28, 2014
Messages
131
Location
Stuart, FL USA
Nice you are advertising but do you have weight, and any real flight testing and recorded hours on them. Has one actually been on a subaru and torsional vibration rpms recorded?
Seems everyone can build a gearbox and advertise. Its not a one size fits all.
The gearbox alone is 26.4lbs. Our total weight with mounting on our 260hp AM20T is 35.8lbs. At this time we have not flown this gearbox and are still in ground testing. Our smaller (225hp on a 4 cylinder) gearbox has flown thousands of hours and the highest hours on a single example is 5500 without overhaul as used on a commercial airboat. At least one customer has used our smaller gearbox on a Subaru that they say is 225hp. We did not do any of the engineering or testing for that installation.

We do not make mounting for the Subaru or LS3 engines. While all of our gearboxes have a hollow prop shaft we do not have provisions for hydraulic CS props. You can use electric like MT, Airmaster, etc.
 

Russell

Active Member
Joined
Nov 29, 2015
Messages
44
Location
Ft Worth, Texas
I wonder why they stopped making them?
George
I spoke with Guy Marcotte about nine months ago ... it sounded as if he is still making his gearbox but in limited numbers. Ray was Guy's machinist and passed away several years ago, I think that was when production slowed down.
 

slociviccoupe

Well-Known Member
Joined
Apr 1, 2011
Messages
316
Location
Palm Bay Fl.
I spoke with Guy Marcotte about nine months ago ... it sounded as if he is still making his gearbox but in limited numbers. Ray was Guy's machinist and passed away several years ago, I think that was when production slowed down.
What are you running. It seems proven.
 

Russell

Active Member
Joined
Nov 29, 2015
Messages
44
Location
Ft Worth, Texas
I have a Marcotte. It has not been 100% trouble free … about 1 ½ years ago I replaced the output shaft and ring gear because I was starting to have spline wear.
I did not know that Marcotte had a website. He is sometimes slow to reply to emails … sometimes as much as three weeks.
 

slociviccoupe

Well-Known Member
Joined
Apr 1, 2011
Messages
316
Location
Palm Bay Fl.
Guy marcote replid to email. He is still selling gearboxes. But no mention of how long gearboxes will be produced and how long replacement parts will be available.
 

Aviacs

Well-Known Member
Joined
Oct 21, 2019
Messages
97
Does anyone know what the gear pitch/profile is in the Marcotte? (Pitch, pressure angle, and form) Sort of assume module, due to being in a decimal country? Did they make the gears or are they sourced from an automotive (or other industrial) app?

Thanks!
smt
 

rv6ejguy

Well-Known Member
Joined
Jun 26, 2012
Messages
3,922
Location
Calgary, Alberta, Canada
Does anyone know what the gear pitch/profile is in the Marcotte? (Pitch, pressure angle, and form) Sort of assume module, due to being in a decimal country? Did they make the gears or are they sourced from an automotive (or other industrial) app?

Thanks!
smt
As far as I know, Guy had the gears custom made. In Canada, most machining/ measuring is still done in English units.
 

slociviccoupe

Well-Known Member
Joined
Apr 1, 2011
Messages
316
Location
Palm Bay Fl.
He is still making them but who knows for how long. Reason i chose spg for my gearbox over the marcote even though the marcost is proven on 2 different planes but both with subaru's on this post.
 

Aviacs

Well-Known Member
Joined
Oct 21, 2019
Messages
97
I suppose my interest is deeper, and possibly quixotic.

A VW based powerplant with a slight gear reduction somewhere between 5:4 & 3:2 (does not have to be integral ratio, but that range, more or less) would offer a lot of improved characteristics for many airplanes. And no, i have not figured out at what ratio & pitch the teeth interfere yet. :) Mostly through the better efficiencies of longer propellers and greatly increased thrust potential. IOW, better take off & climb with no speed penalty. Isolating many of the prop loads from the crankshaft would be useful & there is opportunity to mitigate TV issues.

An internal gear and ring would minimize the need to move the engine location more than a couple inches yet potentially be more robust than planetary systems with a simpler, lighter configuration.

Does anyone know how much the Subaru Marcotte costs? I gather it weighs 40lbs +?

smt
 

rv6ejguy

Well-Known Member
Joined
Jun 26, 2012
Messages
3,922
Location
Calgary, Alberta, Canada
I think cooling a geared VW would be a concern at the higher hp you'd make. Marcotte used to make smaller versions 150 and 200 which were much smaller and lighter. Pretty sure they don't produce the 150 any more and maybe not the 200 either. I believe the M-300 is over $4KUS now and is too heavy for a VW. Mine is around 47 pounds.
 

slociviccoupe

Well-Known Member
Joined
Apr 1, 2011
Messages
316
Location
Palm Bay Fl.
^ correct on the cooling. Also vw's arent cheap anymore. Mag cases are weak, to get big cc's requires max bore and max stroke on an engine design that was intended for 60hp with 4 cylinders. No one makes any good cooling cylinder heads. Not knocking the vw as im building 1/2 of one just for fun. But technology has left the vw behind. Its perfect little engine for small planes and does its purpose. But the subaru is proven.
Spend the same time on a subaru that you would on the vw and you will really come out ahead.
 
Top