BeechTalk - BT - Raptor Aircraft 5 Seat Pressurized 3,600 NM Range Diesel

Username Protected · **Posted:** 13 Oct 2020, 19:49

Thanks for the update. I thought he was busy expanding the envelope and too busy to post new videos.

Just thought it was the flight envelope being expanded not the cooling envelope.

Username Protected · **Posted:** 13 Oct 2020, 19:52

Interesting trade-off... forty pounds of water (plus plumbing). I wonder if the weight budget and space could have been better invested in an auxiliary heat exchanger.

Just thinking out loud.

Username Protected · **Posted:** 13 Oct 2020, 19:55

Username Protected wrote:

Peter put up a new video.... Wants to try some angle brackets ahead of the gear cavity.

Again with the angle brackets!! SMH

Username Protected · **Posted:** 13 Oct 2020, 20:05

Username Protected wrote:

Interesting trade-off... forty pounds of water (plus plumbing). I wonder if the weight budget and space could have been better invested in an auxiliary heat exchanger.

Just thinking out loud.

He's going to trade the 50 lbs added for the lead weights he's carrying in the left seat.

I don't follow what exactly the cooling system is. Does he have a radiator and an oil cooler and a loop for a heater and an intercooler? It seemed like what he was messing with at the scoop was the intercooler, but there had to be a radiator there too, right?

Username Protected · **Posted:** 13 Oct 2020, 20:10

I’m blown away all the air wasn’t sent to the radiator from the beginning.

And how about that Home Depot baffle and dryer vent intake hose! :coffee:

Really though, every bit of air should go through that radiator. I bet that really helps the cooling problem.

And increasing the coolant quantity and using it for favorable CG is a good idea too.

Ramps for the gear wells is silly.

I think the instability came from aft CG. Aft CG and canards don’t mix.

Username Protected · **Posted:** 13 Oct 2020, 20:13

Username Protected wrote:

Interesting trade-off... forty pounds of water (plus plumbing). I wonder if the weight budget and space could have been better invested in an auxiliary heat exchanger.

Just thinking out loud.

He's going to trade the 50 lbs added for the lead weights he's carrying in the left seat.

I don't follow what exactly the cooling system is. Does he have a radiator and an oil cooler and a loop for a heater and an intercooler? It seemed like what he was messing with at the scoop was the intercooler, but there had to be a radiator there too, right?

Username Protected · **Posted:** 13 Oct 2020, 20:48

Username Protected wrote:

And how about that Home Depot baffle and dryer vent intake hose!

Max, I had the same thought! That's about the chintsiest looking solution I could imagine. Glad to see he really took his time with that...

Username Protected · **Posted:** 13 Oct 2020, 20:52

Username Protected wrote:

Where he screwed up is compound turbo'ing with same size turbos. It doesn't work like that and just creates heat and complexity. If you go back to his older videos where you can see the radiator placement, it will never cool no matter how many fans he puts on it.

^^^ This.

You can run twin turbos side by side but we see HUGE increases in efficiency on this engine running a slightly larger turbo in the better-cooled area. It really depends on how you're routing the air, how much intercooling the air charge gets, and engine heat dissipation.

It all works in conjunction with each other and if you tweak one thing, you have to compensate for it. I would suspect that if he could get the IAS up a bit towards 120-140, you'd get better cooling, but that also assumes he doesn't have a back-pressure problem that isn't allowing adequate air flow over the intercoolers/radiators. I'm not convinced that's not a problem.

Username Protected · **Posted:** 13 Oct 2020, 23:43

I don’t know why I continue to watch these videos? I’m amazed PM thought that any cooling air was even going to make it through the coolers without a “back wall” to force air where it is needed. After seeing the solution, it’s clear this guy has given up inside. Zero pride of craftsmanship. I commend his attempt and wish him well, but this nonsense needs to be put to bed.

Username Protected · **Posted:** 13 Oct 2020, 23:52

For those who don’t watch.

This is the new baffle to direct air from the scoop to the radiators. Before all the air just went over the radiator and out the back.

Check out that top of the line material selection.

Username Protected · **Posted:** 14 Oct 2020, 02:18

ok that's maybe enough air for the oil cooler. Now it's time to start on a way to get air for the coolant.

Username Protected · **Posted:** 14 Oct 2020, 02:56

Let’s add 5 gallons of coolant and gain 60 more seconds......

Username Protected · **Posted:** 14 Oct 2020, 06:52

“ Check out that top of the line material selection.”

Not too bad. I thought he’d stick to the cardboard version.

Username Protected · **Posted:** 14 Oct 2020, 07:02

Username Protected wrote:

Where he screwed up is compound turbo'ing with same size turbos. It doesn't work like that and just creates heat and complexity. If you go back to his older videos where you can see the radiator placement, it will never cool no matter how many fans he puts on it.

I don't understand why you would want compound turbos at all in an airplane application? I'd want one turbo sized for peak efficiency. I'd settle for parallel twins only if the packaging benefits were very compelling.