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10/23 Raptor Video

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BBerson

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It would require a complete rework of all hot and cold piping on the engine. This is the current problem as far as I can make out. No resources in current location to make needed changes beyond taping stuff on to the plane.
I see some twin turbos in parallel. Could he do that for low altitude?
 

pictsidhe

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I see some twin turbos in parallel. Could he do that for low altitude?
He could, but he'd need two new turbos along with new manifolds snd other piping. Twin parallel turbos are usually done either for packaging or slightly less lag. No other benefit. I suppose you could run on one bank at full power if one turbo failed. That would likely need a more complex ECU setup.
It would have the same altitude limitation as a single turbo.
 

BBerson

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If he goes with just one does he have the correct size?
He must do something different eventually.
 

wsimpso1

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I don't understand this YouTube post. I would think that mass flow would be the same all through a series system, volume would change?

rv6ejguy
@michael Onines The 1st stage compressor only flows about half the mass flow needed to feed the 2nd stage compressor. The turbos are not matched correctly as has been stated many times for months now. At low altitude for testing, a single turbo will do the job more efficiently and with less weight
Compressor maps work fine when you are only using one. Stage them and operate at altitude, and it can get you messed up. Yes, the same mass flow is being moved everywhere, but since ambient density is so low at the inlet at altitude that the volume flow rate at the inlet will be really big requiring a much larger first stage turbo. So you have to look at pressures and volume flow rates or using mass flow rates corrected for density... yeah, your atmosphere pressure, density, and temperature must be accounted for...
 

pictsidhe

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Yesterday, Andreas said his single turbo would add 30% more power. But he isn't a turbo specialist, he did ECU at Audi.
Just looked at the numbers again.
Ideally Peter needs a custom large frame LP turbo and custom mid frame HP turbo. He currently has two small frame turbos. His HP compressor is about right, but it's turbine is far too small.

Here's the diagrams for his existing turbos and the ones he needs. Within a frame size, dimensions don't change drastically.

A quick look should reveal that getting these on is not a simple job.
 

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rv6ejguy

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When I match turbos for aircraft, I usually do the calcs at SL full power, 8000 feet at cruise power and max anticipated altitude at full and cruise power. At altitude, you need to be sure you stay away from surge at low power settings especially.
 

flywheel1935

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Why did the E-Go not succeed? Seems like a perfectly viable little idea, economical and sporty.
As I understand, it was far too expensive, possibly up to £100.000, the engine fitted was too low on power & it was designed to a much lower AUW category,then the new
SSDR category upped AUW to 300KG. Seemed to fly OK, but only about 5/6 people ever flew it. Was built about 30 miles from my house, and I looked at helping out, but company folded after 1st customer aircraft was delivered.
 

BBerson

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Here's the diagrams for his existing turbos and the ones he needs.
I think he needs to review what sort of system is best for the existing research prototype and it's limited capability. Could be much different from his eventual product, if any.
 

BJC

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If someone threw the Raptor project into my lap, and I had to move the overall project forward, I would pull everything aft of the firewall, and install a Continental TSIO-550 of 350 HP, remove everything not essential to flight, and test and refine the airframe and flight control systems.

If the results were reasonable and salable, (big ifs) I would add basic interior and an installed oxygen system, and start limited production.

I would find one of the auto engine conversion proponents that continually proclaim the superiority of auto conversions for aircraft, and give him the Diesel to play with, or either sell it to the local bus company. If he were to get the entire system running reliably on a test stand, I would look for a customer to install it.


BJC
 

pictsidhe

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I think he needs to review what sort of system is best for the existing research prototype and it's limited capability. Could be much different from his eventual product, if any.
The quick and dirty fix right now is to pull the LP turbo off and check the remaining turbo has the biggest housing option. A better sized single turbo would give a further improvement, but would be a custom mid frame that might sort of fit under the cowl. If he wants to fly high, he will need properly matched compound turbos.
 
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flywheel1935

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I think he needs to review what sort of system is best for the existing research prototype and it's limited capability. Could be much different from his eventual product, if any.
Think the big issue here is that PM regards the current Raptor, as 'Production Aircraft Number One' & not a research prototype, hence that's why it's full of excess crap, like Leather seats, A/Con, Retractable U/C, ponsy rudder pedals,etc.To be honest I would be very surprised if ever a Raptor No2 is ever going to be built. Would you buy an unknown product from an unknown company designed and built by an 'amature' aircraft designer, I don't think so !!!
 

BBerson

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Many companies display non-flying promotion structures at Airventure. Might be another name but I couldn't think of it. I think deciding how much testing or switching it to just static promotion is his most important next step. Continuing these low performance public tests may not be it's best use for promotion.
 
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