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A no-comprise RV-10 (crazy idea)

A

AmontgoRV

Member
I've been reading about the UL520T engine and had a crazy idea. Curious to hear folks' thoughts...

The UL520T engine generates 220hp from sea level to 15,000 feet. At typical RV10 cruising altitudes of 6,500-10,500 ft, this engine would theoretically perform better than an IO-540-D4A5. I'm guessing we would see about 5-7 kts improvement in KTAS going from D4A5 to the 520T at the aforementioned cruise altitudes with comparable fuel flow settings. Also, the 520T might allow for a more aerodynamic cowl because of its better cooling properties. I imagine that a 520T-powered RV-10 could cruise at ~180 kts at 9,500ft on less than 15 gph. Interestingly, the 520T is around 120-150lbs lighter than the IO-540. This means that the 520T would need to hang farther forward on a modified engine mount in order to compensate for the W&B effects. If this mount were to be engineered/installed far enough forward, it could potentially create enough room for a BRS parachute to be mounted in the front of the aircraft, with the weight penalty of the chute offset by the reduced engine weight. This would also solve the current issue with RV-10s where installation of a parachute consumes nearly half of the baggage area.

If the above ideas were possible, one could imagine a 180kt+ RV-10 with FADEC controls, a BRS chute, increased useful load, extra baggage space, and expanded fuel optionality. That would be one heck of an airplane with virtually no compromises (in my opinion)!

Alright, now someone please tell me how crazy I am...
 
I don’t think I want to land by parachute but it would be nice to have a forward baggage compartment.

This would require quite a bit of redesign I think and as such would be out of the scope of builders like me until a proven set of sensible design changes emerges.

If you guys get going on this quickly I might be able to follow in your footsteps.

My questions so far:

1. Would max gross weight be lower with 220HP takeoff power? What would it be?

2. What would be expected takeoff climb at max gross assuming the machine can produce only 220HP?

3. What reasonable modifications could increase takeoff and initial climb out performance without sacrificing reliability? (E.g. waste gate temporary closure, increased compression ratio.)

Like I said this is out of my element here so my questions may be the wrong ones. What are the right ones?
 
Takeoff and climb would be somewhat anemic, but the higher you go in altitude the better the cruise becomes.
 
I really like the idea of the ul520t in an rv10 and reached out a year ago for pricing when they were working on a firewall forward package for the rv10.

The price was right, around $46,000 was the quote last February with a 6 week estimated lead time.

Depending on your location and D.A. the lack of 40hp (assuming the standard 260hp io530) may not be as big of an issue as guys first think. Hot summer days here in nw Missouri can regularly see 3500-4500 d.a. and that's taking a decent percentage off the naturally aspirated io540 power.

The bigger task would be hanging it far enough forward to keep CG acceptable in my opinion. Cool idea for sure though!
 
Substantial amount of design work would be necessary and likely outside the scope of most builders.

I think one of the designers commented in a different thread about the use of the 210 hp continental. It wasn’t a good match.

As far as the chute, that’s a personal decision; it takes a bunch of room and weighs around 80 pounds. Unless you are flying over inhospitable terrain, what valid reason would there be to have it? Not judging, it’s a question to get you to think about when you would realistically use it.

I typically cruise my -10 in the 9000’ +/- range at 174 ktas and 11 gph.

The question becomes “is the effort worth the reward?”
 
Not that I would recommend flying an RV-10 on 220hp, especially not if you live at a place with high elevation and/or high temperatures, but if you really wanted to do it... It's worth pointing out that (A) Van's publishes RV-10 performance numbers with a 230 hp engine, and these numbers have been out since early in the life of the RV-10, I don't know whether they come from analysis or flight-test but they do exist... and (B) Some RV-10s fly with the 230-horsepower SMA diesel engine, so, you could ask them what kind of climb rates they see. Your 220hp is not that far from their 230hp.

Of course, you'd need the engine to move forward quite a bit, maybe add a dorsal fin for directional stability... You'd end up looking a lot like the Rotax RV-9.

As for the parachute, you would not be the first to put a parachute between the panel and the firewall on an RV. It would take some creative sheet-metal work, but not impossible. One problem on the RV-10 (and on slider-canopy RV-6/7/9s) is the diagonal strut just aft of the windscreen that goes from the ceiling into that space where the parachute would be. The parachute would be on the load path that holds the airplane if it ends up inverted on the ground. So the parachute box, or the parachute itself, should be able to take that compressive load. Again, not impossible, but not easy.
 
AirShowFan said:
Not that I would recommend flying an RV-10 on 220hp, especially not if you live at a place with high elevation and/or high temperatures, but if you really wanted to do it... It's worth pointing out that (A) Van's publishes RV-10 performance numbers with a 230 hp engine, and these numbers have been out since early in the life of the RV-10, I don't know whether they come from analysis or flight-test but they do exist... and (B) Some RV-10s fly with the 230-horsepower SMA diesel engine, so, you could ask them what kind of climb rates they see. Your 220hp is not that far from their 230hp.

Of course, you'd need the engine to move forward quite a bit, maybe add a dorsal fin for directional stability... You'd end up looking a lot like the Rotax RV-9.

As for the parachute, you would not be the first to put a parachute between the panel and the firewall on an RV. It would take some creative sheet-metal work, but not impossible. One problem on the RV-10 (and on slider-canopy RV-6/7/9s) is the diagonal strut just aft of the windscreen that goes from the ceiling into that space where the parachute would be. The parachute would be on the load path that holds the airplane if it ends up inverted on the ground. So the parachute box, or the parachute itself, should be able to take that compressive load. Again, not impossible, but not easy.
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I'll stay with what I have, but at high temps and altitudes (high DAs), the 220 HP turbocharged engine might exceed the performance of the D4A5. DAs here are often 6,000'+ in the summer. My Lycoming isn't making anywhere near 260HP under those conditions. Depending on the prop, I'd agree that the 230 HP data from Van's would give a reasonably close approximation of what you might expect at sea level.
 
tom_AZ said:
Iat high temps and altitudes (high DAs), the 220 HP turbocharged engine might exceed the performance of the D4A5.
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Good point. If the 220hp engine is turbocharged, then hot/high would not be a problem, and could in fact be an advantage over the 260hp IO-540.

Is it true that you lose ~3% power for every 1000 feet? If so, then a 260 hp IO-540 is making ~230 hp at ~3800 ft DA, and 220 hp at ~5100 ft DA. Higher than that, and the lower-horsepower turbo'ed engine would be more powerful.
 
It would be a lot easier to build a Turbo Normalised IO540D4A5. It has been done and works fine in an RV10.

Otherwise it is a solution looking for a problem and a whole lot of pain to get there.
 
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