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260hp RV7?

TheToad

I'm New Here
I feel like an Aeromomentum AM20T, would make an awesome engine in an RV7... its a couple pounds heavier than a Lycoming o325 yet makes 45 more hp than a Lycoming io390... and costs less than either Lycoming... and is turbocharged which will mean much better performance at altitude... am I missing something? Thoughts?
 
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With regards to the "better performance at altitude" point, I'll direct you to the classic text from the mothership: https://www.vansaircraft.com/wp-content/uploads/2019/01/hp_limts.pdf

Apologies if you've read it already. If you haven't, it's vital reading.

To summarize the takeaway, the main benefit you can expect from extra horses is a better climb rate. You're not going to get much more speed out of the plane without bumping against Vne. If you really want to go faster, you may want to look into something like the F1 Rocket, which is designed with a higher Vne.
 
Looks like a snowmobile engine.. I spent a week beating up a Yamaha snowmobile, and man, they are impressive..screaming all day long, never missed a beat. I still don’t think I want to fly behind one at night, over the mountains..

as for the aero AM20T, you’ll have to use a gearbox, probably an electric adjustable prop, water cooling system, wiring and high pressure fuel system, all the while, you’ll probably kill the resale value of your RV (if that maters to you) I say go for it! Let’s see how it works out!
 
... am I missing something? Thoughts?
It all depends on how much experimenting you like to do. These numbers are impressive - you just need to make them real in your aircraft. Quite a long road. Not trying to be a buzzkiller, but there are dozens of threads like this on VAF and other sites like it.
 
Van's has done the engineering, design and flight testing of their aircraft using the recommended engines specified for each model. Going "outside " the box on your powerplant opens up a whole new can of worms and with that comes your own engineering, design and flight testing. Adapting a modified auto engine to your bird is a challenging task, that may seem economical on paper, but in the real world can prove to be quite a monumental undertaking. Engine mount, cowlings, fuel system, cooling & propeller, just to mention a few will need to be addressed, adding countless hours of build time. If you are considering this based solely on cost, then don't do it, stick with a Lycoming and shop around for a good deal. If however you are willing to take on these challenges, then go for it. As mentioned, your resale value will go down the toilet. The list of "successful" auto conversions Subaru, Mazda, Chevy etc: is fairly small, and many of these aircraft have since been converted back to conventional aircraft power.
 
With regards to the "better performance at altitude" point, I'll direct you to the classic text from the mothership: https://www.vansaircraft.com/wp-content/uploads/2019/01/hp_limts.pdf

Apologies if you've read it already. If you haven't, it's vital reading.

To summarize the takeaway, the main benefit you can expect from extra horses is a better climb rate. You're not going to get much more speed out of the plane without bumping against Vne. If you really want to go faster, you may want to look into something like the F1 Rocket, which is designed with a higher Vne.


I'm not interested in going faster... im interested in an awesome climb rate... 😁
 
Any time you go to an auto conversion vendor website and they show cad drawings or bare engines, be very afraid. You want to see engines cowled up in flying airplanes. Lot and lots of them.
 
So...I don't want to be one of those guys who is automatically against change, but any time you start going out into uncharted waters with something like this, you've got to accept the fact that it's potentially going to cost twice as much and take twice as long as you've budgeted.

I'm not familiar with the engine you're talking about, but just off the top of my head, I suspect that your going to be in for a ton of custom made parts; engine mount, hoses, cooling system, throttle linkages, etc. That will likely eat up any $ savings and then some.

As far as performance with a bigger engine, yeah, thrust is cool, but the rocket guys have a bigger engine and they have to do some stuff to the airframe to make it play nice with all that extra zip
 
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I feel like an Aeromomentum AM20T, would make an awesome engine in an RV7... its a couple pounds heavier than a Lycoming o320 yet makes 45 more hp than a Lycoming io390... and costs less than either Lycoming... and is turbocharged which will mean much better performance at altitude... am I missing something? Thoughts?

Sounds interesting and puts the Experimental into amateur built. What you are missing is it will not be an RV7 when done. At a minimum the wing, tail surfaces, and all the controls surfaces will need to be stiffened for the new Vne. How much will require some analysis and maybe even some test parts. I know you say in a later post you only want climb performance of the added HP, but it will be awfully hard to keep temptation to not bump up the throttle in cruise. Engine mount and cowl will be brand new. Cooling will require some thought.
My Thoughts, the difference in price of the engine will be far exceeded by the custom work required to make engine fit an “RV like” fuselage and allow the increase in Vne. It needs to be designed for the increased Vne if I was the one signing it off.
If you take on such a project, I hope you post often here so we can all learn (and critique).
 
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There are lots of turbine aircraft that can bust redline airspeed in level flight. Apparently the Dash-8-Q400 can bust redline speed with an engine shut off! The key is to watch the speed and respect the limits. One just needs to realize that the most power they can use for normal cruise flight will be in the vicinity of 160hp. So a 260hp engine can't use more than about 60% in level cruise flight. Sure if you want to have some fun, a short burst of 200hp (77% power) will bring it up to Vne, but that's well into the yellow range, so respect the limits and don't stay there very long.

The caveat is that airplanes with the power and performance available to exceed redline airspeed also require more pilot training than a single engine piston plane. All that performance can get away from a person who isn't used to it or trained for it.

I suppose the point of all this is to say power is great, means it climbs very fast. Once level, that power can be a determent and makes flying the plane within the limits more difficult. That's why Van's strongly recommends against installing too much power (or turbos). That additional difficulty requires more training, and training that is difficult to come by.
 
powerwise, nothing new here... Super -7 (and -6, and...) already exist and fly, not with a meager 260, but rather 300hp :D

Maybe those of us running 360's in our 9/9A should put a vinyl sticker on the tail - "Super 9" or "RV9-SS" :D
 
Wow, thanks for all the info... especially the rocket F1 stuff! Looks like I'll be beefing up the fuselage and tail also! 200+ cruise with sub200meter takeoff and 2,500+fpm climb sounds like exactly what im after.... I own a sheet metal shop, and custom building motorsports related stuff is one of my favorite things to do... throttle control isn't an issue for me.
 
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Wow, thanks for all the info... especially the rocket F1 stuff! Looks like I'll be beefing up the fuselage and tail also! 200+ cruise with sub200meter takeoff and 2,500+fpm climb sounds awesome!

Id put this engine in one if i thought i could offset the weight increase.... maybe lead weights in the tail?
https://www.gmperformancemotor.com/parts/19421004.html
 
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L45 IS Rocket Mecca

Hey TheToad,

Sounds like you need to take a trip to L45 (Bakersfield) to get Rocket and Vans inspired. Man, those boys down there have a LOT going on! Get hold of the EAA there, and look out! Wait until Harmon shows up and reveals the gems they have. :D
 
Id put this engine in one if i thought i could offset the weight increase.... maybe lead weights in the tail?
https://www.gmperformancemotor.com/parts/19421004.html

An RV isn't the right airframe for something like this. Consider a Glasair III or Lancair Legacy which can better accept the weight and hp.

You'll need a considerable background in design, engines, gearboxes, fabrication and welding to make something like this happen or be willing to pay those who have. Dreams are great but the execution of such a swap successfully is grounded in reality.
 
I feel like an Aeromomentum AM20T, would make an awesome engine in an RV7... its a couple pounds heavier than a Lycoming o325 yet makes 45 more hp than a Lycoming io390... and costs less than either Lycoming... and is turbocharged which will mean much better performance at altitude... am I missing something? Thoughts?

We're currently building a Zenith CH750 and just sold our AeroMomentum AM15 and purchased a Rotax instead.
The reasons were massive delays, an incomplete / poorly fitting firewall forward 'kit' and increasing concerns about the quality of the engine's auxiliary components (alternator, starter, coil pack, ECU, etc.).

Mark is a knowledgeable, nice guy and a super smooth talker - delivering on his promises, designing fwf kits and managing suppliers aren't however exactly his strengths.

According to their website the latest status of the AM20T is apparently that it is still sitting on a pallet: http://www.aeromomentum.com/am20t.html His Facebook also doesn't show anything more current about this engine.
 
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There has been a Super8 where someone fitted an IO540 to the RV8. Has anyone tried to stuff a 540 engine to the RV7 and call it a Super-7. This is probably an easier proposition than using a modified car engine. I can't believe people haven't tried this on an RV14.
 
Here is a guy that installed the Yamaha motor in a Kitfox..... https://www.youtube.com/watch?v=BibiTUv9DYA

I’ve flown the 300 HP turbo Yamaha in a Highlander, and it is awesome - at least for a STOL play-plane. I don’t know what the lifetime will be, or the lifetime reliability in terms of just “getting in the airplane and flying it” whenever you want. The price you pay for really high performance is usually lots of tinkering and fixing....

Paul
 
Here is a guy that installed the Yamaha motor in a Kitfox..... https://www.youtube.com/watch?v=BibiTUv9DYA

Steve Henry has been the guru in the Yamaha Apex world, which Bryan Bowen (Project Kitfox) has just flown, and documented on his YouTube channel. He benefited enormously from the small-but-robust aero-conversion infrastructure, including Steve Henry, for things like engine mounts, firewall-forward, exhaust and especially the gearbox from Skytrax and tuning advice from Brian Dacus... If you watch the Project Kitfox series, you'll see that stepping that far outside the box is not without more than its share of tinkering. Aeromomentum appears to be subtantially farther outside that box. I think you'd be pretty much on your own, and relying on Aeromomentum's customer service.

I could see this Aeromomentum engine as a great Experimental aviation project, but unless there's a substantial support structure behind it, I see it mostly as a big headache.
 
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I would in a heartbeat! If anything, just to watch the indignant reactions.

Wonder what it would cost to license the Every-Ready black-cat 9-volt battery logo? :D
 

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There was an LS powered 7 back about a decade ago. Predator Aircraft or something like that. Should have had a lot more than 260hp and a lot of lead in the tail I expect.
 
An LS7 powered 7 would make the most sense to me... 🤷*♂️🤣

Here ya go:

LS powered RV7 (1024x576).jpg

I don't know the particulars but a friend of mine bought this one, got it flying then sold it. Word has it that it scared a test pilot pretty good.

-Marc
 
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