New Gear Box?

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TXFlyGuy

Well-Known Member

Is this new here? Any thoughts on this design?

wsimpso1

Super Moderator
Staff member
New to me. They talk a good story, and collaborating with EPI is a good move.

A long time ago I learned "In God we trust. All others bring data." No data... We have no idea if it is good, debugged, and been run a long time, or if it has never been run and might have lots of little things wrong.

You are a current Autoflight customer and might be interested in their box. Ask a few questions:

How much run time do they have on what engine and dutycycle?
How much flight time on how many gearboxes do they have?
Any failures? What was improved after failures?
Is their governor and prop hub being fed filtered oil or just whatever is in the sump?

Billski

sming

Well-Known Member
@wsimpso1 It looks like it's the norvegian guys that are developping a (600HP?) BMW based V12 for airplanes. From afar it looks top notch and very expensive...

They've got extensive videos on YouTube now :

J Galt

Well-Known Member
Supporting Member
Ole has done a lot of good work. That PSRU has been around awhile, Jack Kane has a lengthy write-up on the various versions on the EPI site. It is single mesh so that means you need a reverse rotation engine (or prop). It seems promising.
Justin

Looks like he mentioned a dual mesh being an option with new housings, meaning no reverse rotation engine or prop needed. (Reverse being counterclockwise when viewed from cockpit).

TXFlyGuy

Well-Known Member
This is very interesting. Yes, thought it would turn backwards!

Well-Known Member
New to me. They talk a good story, and collaborating with EPI is a good move.

A long time ago I learned "In God we trust. All others bring data." No data... We have no idea if it is good, debugged, and been run a long time, or if it has never been run and might have lots of little things wrong.

You are a current Autoflight customer and might be interested in their box. Ask a few questions:

How much run time do they have on what engine and dutycycle?
How much flight time on how many gearboxes do they have?
Any failures? What was improved after failures?
Is their governor and prop hub being fed filtered oil or just whatever is in the sump?

Billski

Also:

What range of prop inertias is it designed for / tested with.

Malish

Well-Known Member
New to me. They talk a good story, and collaborating with EPI is a good move.

A long time ago I learned "In God we trust. All others bring data." No data... We have no idea if it is good, debugged, and been run a long time, or if it has never been run and might have lots of little things wrong.

You are a current Autoflight customer and might be interested in their box. Ask a few questions:

How much run time do they have on what engine and dutycycle?
How much flight time on how many gearboxes do they have?
Any failures? What was improved after failures?
Is their governor and prop hub being fed filtered oil or just whatever is in the sump?

Billski

What is about gearboxes from Stinger Drives? Is anyone used them in aircraft?

wsimpso1

Super Moderator
Staff member
What is about gearboxes from Stinger Drives? Is anyone used them in aircraft?
Stinger and Ballistic both are gear drive, have a good reputation in airboats, and both will not drive an oil actuated constant speed prop - Either fixed pitch or electric constant speed props.

pfarber

Well-Known Member
Sounds like that PSRU is specifically for their scaled v12 motor.

It emphasizes aerobatic flight, something 99% of homebuilts will never need.

So while most likely a neat project... its not something you're bolt to an LS1 anytime soon... and at the price I can guess at, you could simply buy a certificated motor and wrench on it yourself.

There are about half a dozen PSRUs that cost less than $5k and can handle 400hp.. that's basically every E/AB motor out there. Its a great science project, but very very very very niche. KeithO Well-Known Member To educate us mere mortals, could you name those drives ? Because the market seems very thin right now. 1. We can leave out EPI since they clearly have no intention of actually doing any production, just expensive paid for development projects with perhaps 1 or 2 samples made (or not). 2. The French Canadian is gone too (Marcotte). 3. Firewall forward also gone. Was a belt drive anyway. 4. RWS aka Tracy Crook long gone. He had a series of concentric style gearboxes based on automatic transmission parts that seemed robust at 200-300hp level. 5. Ross, gone. 6. Ballistic will no longer sell into aviation applications. So off the list. Who does that leave exactly ? 7. There is the Rotax E box. Perhaps OK up to 90hp. 8. Viking making gearboxes but to get one you have to buy the engine too (package deal only).$13k-$20k for a package at current prices.$10k for the 90hp 3 cylinder Mitsubishi. Too expensive for the gearbox alone on any of them.
9. Then there is Aeromomentum. They have a box rated up to I believe 225hp just 1 ratio. I am also lead to believe that due to customer demand for a bigger offset for vertical engines they are now developing a new 3 gear set. So perhaps the original 2 gear box might be abandoned ? Mark will sell to DIYers even if you are theoretically competing with him on the engine side.
10. Skytrax, making very high quality (machined from billet housings) 3 gear gearboxes. So far only for the Yamaha 2, 3 and 4 cylinder engine families. The 3 cylinder turbo I believe is up to 200hp and some of their other gearboxes have been used up to 300hp for STOL competitions. For now all their resources are being sunk into the Yamaha engines and making enough gearboxes to satisfy the thirst of the STOL crowd, who have been very much popularized on youtube in recent times. See what has happened to Kitfox kit prices and lead times....
Is there anything I have missed (ignoring the belt drive options) ?

Sounds like that PSRU is specifically for their scaled v12 motor.

It emphasizes aerobatic flight, something 99% of homebuilts will never need.

So while most likely a neat project... its not something you're bolt to an LS1 anytime soon... and at the price I can guess at, you could simply buy a certificated motor and wrench on it yourself.

There are about half a dozen PSRUs that cost less than $5k and can handle 400hp.. that's basically every E/AB motor out there. Its a great science project, but very very very very niche. wsimpso1 Super Moderator Staff member Sounds like that PSRU is specifically for their scaled v12 motor. I suspect it could be adapted and would have a broader market if an LS version were made. The coupling might be more challenging for a V8 than a V12. It emphasizes aerobatic flight, something 99% of homebuilts will never need. All certified airplanes have to be capable of spin entries/recoveries and some negative g (engine can stop but must re-start) and none of that can tear up the engine. Pretty good idea to do that in our homebuilts to. Aerobatically capable adds only modest weight, so it is not much detriment. So while most likely a neat project... its not something you're bolt to an LS1 anytime soon... and at the price I can guess at, you could simply buy a certificated motor and wrench on it yourself. There are about half a dozen PSRUs that cost less than$5k and can handle 400hp.. that's basically every E/AB motor out there.

Its a great science project, but very very very very niche.

Pretty much agree ... well, I know Ballistic. Stinger looks good. Who are the others that are solid?

Billski

PMD

Well-Known Member
I certainly agree with their comments about using a simple engine, but honestly thought the even/uneven fire stuff was a cheap shot. After all: RED seems to be able to make similar power with a far more appropriate fuel using uneven firing and manages EASA certification. As a sidenote: I really don't like uneven fire either, but I will go with proven hardware any time (we even drive an uneven fire V6 every day).

If someone was to come to me and tell me I had to build a 500+ HP gasoline (YUCK!!!!!) fueled engine, I would simply go out and buy an Orenda off the shelf. If I wanted to sell more than one, I would expect to be able to pick up the tooling and type certification (and possibly production certificates) by purchasing the leftovers at Trace. To base a business on a low volume automobile engine that went out of production 20 years ago seems a bit risky compared with having essentially the same block metallurgy but ALL of the tooling under your own roof- and FAA certification.

wsimpso1

Super Moderator
Staff member
I do not get the 'cheap shot" reference.

90 degree V-12's will require isolators designed with spring rates, travel, and torque capacity about the same as if the engine was a V-6 with the same torque curve. That will drive a spring rate in the isolator for the 90 degree V-12 to about one-quarter that for the even fire V-12. Travel beyond the mean travel at max torque will also have to be quadrupled too. This is not to say that total travel is quadrupled, just the amount of vibratory deflection around the max torque deflection. This is all just vibration theory - an ME junior year class - extended into rotation from linear...

V-8's of similar power will be a little easier to isolate than the 90 degree V-12, but harder than the even fire V-12.

Looking at the parts, see those hollow shafts with splines on the ends? That appears to be three torsionally springy quill shafts that nest inside each other so that they make a nice soft spring. I believe that is the isolator spring. A new one would probably have to be designed for each engine and firing pace.

Billski

Air Trikes

Well-Known Member
Is there anything I have missed (ignoring the belt drive options) ?
SPG gearboxes are in production for 20+ years, more than 3000 units are made. Most of them are used for aviation. There are 3 SPG gearboxes in production now, different ratios, different bellhousings for Subaru, Honda, Suzuki, BMW, Toyota engines, recommended up to 130, 180 and 350-400 HP. Many of them are flying in USA and Canada. More info Air Trikes: Engines and Conversion Kits.

PMD

Well-Known Member
I do not get the 'cheap shot" reference.

Billski
IF you were seriously considering their very expensive auto engine conversion of the 60 degree, even firing BMTroubleyou the ONLY cross shopping would be the RED V12 - an 80 degree uneven fire engine. Thus IMHO a subtle cheap shot at a fully certified and proven competitor.

MACOWA

Well-Known Member
Supporting Member
I do not get the 'cheap shot" reference.

90 degree V-12's will require isolators designed with spring rates, travel, and torque capacity about the same as if the engine was a V-6 with the same torque curve. That will drive a spring rate in the isolator for the 90 degree V-12 to about one-quarter that for the even fire V-12. Travel beyond the mean travel at max torque will also have to be quadrupled too. This is not to say that total travel is quadrupled, just the amount of vibratory deflection around the max torque deflection. This is all just vibration theory - an ME junior year class - extended into rotation from linear...

V-8's of similar power will be a little easier to isolate than the 90 degree V-12, but harder than the even fire V-12.

Looking at the parts, see those hollow shafts with splines on the ends? That appears to be three torsionally springy quill shafts that nest inside each other so that they make a nice soft spring. I believe that is the isolator spring. A new one would probably have to be designed for each engine and firing pace.

Billski
Good shot ! my ford coyote motor uses torsionally springy cam shafts for VVT.

J Galt

Well-Known Member
Supporting Member
Thank you for splitting off the political/other PSRU talk.

Regarding this one, it was originally made to be able to mate up to a LS or big block Chevy. This is a modified version of EPI's MK 15:

I'm not sure what differences there are. Ole had a minor injury so he's been out a bit but I'm sure when he's going again he can update us all.

Justin

wsimpso1

Super Moderator
Staff member
I do not get the 'cheap shot" reference.

Billski
IF you were seriously considering their very expensive auto engine conversion of the 60 degree, even firing BMTroubleyou the ONLY cross shopping would be the RED V12 - an 80 degree uneven fire engine. Thus IMHO a subtle cheap shot at a fully certified and proven competitor.

I still do not know where the "cheap shot" was. A "reply" to a post with the text pointed out really helps in finding the offensive post, as would the post number (upper right corner of each post on a thread). Or perhaps hit the report key on the post and then detail the issue so we overworked unpaid moderators can find it.

Billski