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MEDEVAC

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Apr 22, 2020
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Brisbane, Australia
Hi Rik, you’ve certainly got my attention! :p

an engine developer (EPI Inc, www.epi-eng.com) was developing a race engine for the aircraft with approx 1850hp.

“The first is a naturally aspirated version that will produce 810 bhp at 4800 RPM (but not with the short stacks shown in the preceding pictures). The second is a gear-driven-supercharger version, which provides the “authenticity” required by certain builders for replica WWII aircraft engines, and is expected to produce about 1225 hp at 4800-5000 RPM with a nominal boost level and good aftercooling. The third is a heavily turbocharged-and-aftercooled race version that is expected to produce more than 1750 hp at 6000 RPM.”

Like so many projects, this too came to nothing. So I’m looking for options.

The T53 looks like it puts out around 1400 hp. Does it have the gearbox integrated and what is the output RPM? If you had a datasheet with the dimensions and weight and of course cost and were happy to share, I certainly wouldn’t rule it out! Thanks for the idea!
 

TFF

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Apr 28, 2010
Messages
13,600
Location
Memphis, TN
A Legend has pretty much the same capacity.

If the airframe can handle it, two hours at 25,000 ft at 250 kts gets you pretty far down range because your true airspeed is up around 400. If you can’t get the altitude, you are not going far. If it’s really only a 30 minute toy on a Saturday, it doesn’t mater.

A piston plane would have you around 15,000 ft at 200kts. Your moving good but what you have on your side is endurance. You could do 250 kts true for four hours and go farther, but did you get there quicker? Faster with a fuel stop might be better if you are that much faster.

I personally would want the piston over the turbine just because I want to hear the engine. But if I was going to fly 150 hours a year traveling, turbine would be the smart way. For the money it’s going to cost, you can get a lot done either way and both ways you have to ramrod the installation because no one can do it but you. Turn it over to someone and the price will triple.
 

Rik-

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Joined
Sep 13, 2019
Messages
413
Location
San Rafael, California
Hi Rik, you’ve certainly got my attention! :p

an engine developer (EPI Inc, www.epi-eng.com) was developing a race engine for the aircraft with approx 1850hp.

“The first is a naturally aspirated version that will produce 810 bhp at 4800 RPM (but not with the short stacks shown in the preceding pictures). The second is a gear-driven-supercharger version, which provides the “authenticity” required by certain builders for replica WWII aircraft engines, and is expected to produce about 1225 hp at 4800-5000 RPM with a nominal boost level and good aftercooling. The third is a heavily turbocharged-and-aftercooled race version that is expected to produce more than 1750 hp at 6000 RPM.”

Like so many projects, this too came to nothing. So I’m looking for options.

The T53 looks like it puts out around 1400 hp. Does it have the gearbox integrated and what is the output RPM? If you had a datasheet with the dimensions and weight and of course cost and were happy to share, I certainly wouldn’t rule it out! Thanks for the idea!
These have an internal planetary gearbox which reduces the RPM down to 6,600 rpm. Just as they went into the Huey gearboxes.

These are a bit more than the 1400 SHP rating as they dyno'd at a bit over 1900 SHP. The engines are basically 48" by 23" diameter. About 550 lbs.

Need more power? Got some T55's L11C's.. 2650 rating but dyno'd at 3,200 shp
 

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MEDEVAC

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Apr 22, 2020
Messages
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Location
Brisbane, Australia
I spoke with them. Great guys am here in Aus but it’s a 90* so has the same harmonics issues as a Falconer. The EPI site goes into some detail. Hard to know how much is due to professional rivalry though - he is scathing of the Falconer design.

Rik - those engines look awesome! How much do they cost though? How expensive are and how heavy is a suitable gearbox? The power is so tempting
 

macquistan

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Mar 25, 2020
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Can you briefly explain the harmonic issues with a 90 degree V12 or post a link to a good explanation, please?
Thanks much.
 

Rik-

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413
Location
San Rafael, California
I spoke with them. Great guys am here in Aus but it’s a 90* so has the same harmonics issues as a Falconer. The EPI site goes into some detail. Hard to know how much is due to professional rivalry though - he is scathing of the Falconer design.

Rik - those engines look awesome! How much do they cost though? How expensive are and how heavy is a suitable gearbox? The power is so tempting
A T53 is in the 75K range for a "Non certified air worthy" model and then you need a reduction unit on top of that. For a aircraft a gearbox would not have to be as robust. Figure 200 lbs.
 

BoKu

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The EPI V12 contractor is a friend whose shop isn't far from me. I have an email in to them to see what's up. I'll let you know if I hear anything.
 

Chris Matheny

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Can you briefly explain the harmonic issues with a 90 degree V12 or post a link to a good explanation, please?
Thanks much.
An odd fire 90 degree V12 (90/-30) has around 70% more peak torque pulse input than a 60 degree even fire engine. From a standpoint of designing a gearbox for it you would need to beef it up a considerably to deal with the extra load.
 

MEDEVAC

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Apr 22, 2020
Messages
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Location
Brisbane, Australia
That’s an excellent and succinct summary!

For anyone that wants a detailed breakdown, look at the pages I linked for EPI. He explains it in great detail.

The Thunders appear to have had a lot of engine and gearbox issues over the years. I’d like to avoid the same fate.
 

macquistan

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Thanks for the explanation, Chris!

MEDEVAC, too bad you couldn't use a GMC 702 V12. You wouldn't need a PSRU, but you might be a bit nose heavy.
 
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BoKu

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interesting - his website suggested it was on hold indefinitely.
Remember that the epi-eng site belongs to Jack Kane, the designer. It's not the site of the guy he designed the engine for, or who is fabricating the assemblies.
 

MEDEVAC

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Apr 22, 2020
Messages
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Location
Brisbane, Australia
A quick look on Barnstormers and I can see a couple of 331-10s with gearboxes included for $80k. I am sure more will becomes available as the airlines and planes stop flying.
I noted that a Turbine Legend has a 331-10 and they get 40GPH.

Here is a question - in the US, do you refer to Imperial GPH (4.544L) or US GPH (3.78L)?

BoKu - did you swing by? What is the machining place at with those V12s please? Keen to hear more!
 

TFF

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I imagine 331s are coming out of J31s and Metroliners. I doubt they are coming out of MU2s, KingAir B100s, or Commanders. I know all the J31s I worked on have been scrapped years ago. Everything corporate is flying in the US, so don’t expect a wave of turboprops being grounded. They are getting more valuable. GE CFM56s will be cheap soon. Don’t think it will fit.
 
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