HPX Goes MASSIVE

[Irvine.J]

Thanks very much guys.
What I'm about to do is install the new reflector cone, its much steeper but with allot less surface area. So what I'm interested in seeing is what influence it will have on the exhaust from the induction pipe. Interestingly as eric mentioned is at full grease when the exhaust gas hits the top of the choke cone, it blows itself apart and no longer looks like that 3D mushroom which is quite mesmerising, I'm looking at augmenting it eventually just for something to do after I trial this new reflector which should be welded on today. I'll post 2 videos afterwards, 1 with the reflector as it currently is one with the new one.

LARRY
I forgot to mention! Check out the heat pattern! Notice the cool section immediately after the choke cone, then it heats up again at the point where the reflector meets the rectifier pipe. Exactly as you described in nudis, damn good work my man! It was hard to see in the smaller engines, but here its very very noticeable isn't it. I actually point at it at the start of the film. Also, notice the hot spot where the tail cone meets the center pipe? That is just weird.

[CG]

Hi James, I just visited your website advertised here, and I must say, it's very nicely done. Nice engine photos too of your engine designs.
I just have one question.
One your webpage for the HPX-D 30 you state the following:

"The HPX-D 30 is an experimental 30lb thrust engine based on the HPX design. More test are currently taking place though the engine is running extremely well and seems quite efficient. It will flame out well before reaching full throttle on a propane tank with a 1/4 inch tube, suggesting that it is running at atleast a 2lb/lb/hr TSFC or less. This engine is the first from Irvine Aeropulse that could be used effectively to power a large UAV or drone aircraft. Even at 1 meter long this engine is so light it can be held comfortably on ones fingertip. Made in 0.5mm stainless steel and comes with fuel filter and Irvine aeropulse "Vector Jet" liquid fuel injectors and fuel lines. Unit price - $650 USD".

My question is, how does the fact that the engine will flame out before reaching full throttle suggest that the TSFC is 2 or less? I don't understand how the one fact leads to the other. Can you explain it for us? Thanks.

[Irvine.J]

Ran it on a thrust stand the other day for about 5 minutes, it burns about 450 ml per minute of liquid fuel at max throttle which is pretty close to 2.0 TSFC. I also weighed the propane tank during a 2 minute run on my load cell which had near same result, so in this case my gut feelings were fairly accurate. I have a new tailpipe to put on this engine which might change a few things, we'll see. Best thing you can do if your just trying to get a ballpark figure is weigh the tank on a load cell and run it for a few minutes at its highest throttle and measure the fuel flow rate over time. Its not super accurate, but its close enough.

I will amend that line to add the fuel rate test data, thanks. Its still an "X" engine which means I still have a few parts I want to change to try and get the most out of it, takes a while I got a lot on atm.
I always test it properly when I get the time.

[CG]

... it burns about 450 ml per minute of liquid fuel at max throttle which is pretty close to 2.0 TSFC

Assuming your liquid fuel was petrol (sp. gr. ~0.68), then
450 ml per minute equals 60.45 liters per hour. With a sp. gr. of 0.68 g per cc, 60.45 liters weighs 41.11 kg.

If your TSFC was 2.0 kg fuel/ kg-thrust / hour, then your max thrust was 20.56 kg, or 45.22 lbs for your "30 lb thrust" motor. Do I understand this correctly?

If your "liquid fuel" was methanol (D 0.79) then your thrust for this motor would be 52.53 lbs!

I seriously doubt your "liquid fuel" was propane since you report the fuel consumption on a volumetric basis (which is an inconvenient measurement, to say the least, for a liquid which rapidly flashes to vapor at reduced pressures) rather than by weight.
If you DID use liquid propane I would be curious as to how you measured a volumetric flowrate rather than a mass flow rate for this substance?

Which liquid fuel did you use and what was your recorded thrust in either kilograms or pounds?
What is the mean diameter of your combustion chamber?
Thanks for helping; I'm trying to understand your data.
And keep up the good work, those are nice engine builds!

[Eric]

Assuming your liquid fuel was petrol (sp. gr. ~0.68), then
450 ml per minute equals 60.45 liters per hour. With a sp. gr. of 0.68 g per cc, 60.45 liters weighs 41.11 kg.

If your TSFC was 2.0 kg fuel/ kg-thrust / hour, then your max thrust was 20.56 kg, or 45.22 lbs for your "30 lb thrust" motor. Do I understand this correctly?

If your "liquid fuel" was methanol (D 0.79) then your thrust for this motor would be 52.53 lbs!

I seriously doubt your "liquid fuel" was propane since you report the fuel consumption on a volumetric basis (which is an inconvenient measurement, to say the least, for a liquid which rapidly flashes to vapor at reduced pressures) rather than by weight.
If you DID use liquid propane I would be curious as to how you measured a volumetric flowrate rather than a mass flow rate for this substance?

Which liquid fuel did you use and what was your recorded thrust in either kilograms or pounds?
What is the mean diameter of your combustion chamber?
Thanks for helping; I'm trying to understand your data.
And keep up the good work, those are nice engine builds!

My bet is that it was hydrogen at STP for a net thrust of about a gram.

Oh yea 450 ml a minute is something like 27 liters an hour if my brain is working, so those figures would be a little under half, so reasonable for a 30 lb design.

Eric

[Irvine.J]

Hmm, forgive me for thinking you sound quite hostile.
30 lbs of thrust at 1lb fuel per minute is 2.0 LBS. Not kg, thats where your confused. (or 60lbs of fuel burned per hour / 30lbs of thrust = 2) Pretty simple yeah, 450 grams is pretty much 1lb, so I used 1 lb, sorry if that confused you.

I do not need run "Liquid propane" in this engine either.

I seriously doubt your "liquid fuel" was propane since you report the fuel consumption on a volumetric basis (which is an inconvenient measurement, to say the least, for a liquid which rapidly flashes to vapor at reduced pressures) rather than by weight.
If you DID use liquid propane I would be curious as to how you measured a volumetric flowrate rather than a mass flow rate for this substance?

You've completely misread what I said. I run it on vapour, and measure the tank weight difference. Though liquid (Kerosene) is a much better indicator.

Eric: Brain working or not as usual you are spot on.

[Bent]

Hey James...I'm sure glad I don't know what you guys are trying to figure out But if I ever do need to know this stuff, I will just refer myself to you, if thats ok
and yes... that is 1 sweet engine you have there
I love this site

[CG]

Oops, you're right, 450 ml is 27 liters per hour (my fat fingers...)
Sooo, that's 27 kg /hr times .69 equals 18.36 kg per hour fuel consumption...TSFC is 2.0 so thrust equals 9.18 kg or 20.2 lbs for this motor.

However, I now understand you didn't use liquid fuel, just propane vapor and extrapolated the tank weight change to a volumetric measure and used the density of liquid propane for your calculation.

So now, if I understand you correctly, the engine produced EXACTLY 30 lbs of thrust for five minutes and in so doing burned 5 lbs of propane (as the vapor). Have I got it right now? [You should've just said so in the first place, and on your website; it've been a whole lot less confusing...]

Not being hostile, just trying to understand your results / statements. That first statement on your website didn't make sense to me. Sorry for the confusion, and my bad math.

[Irvine.J]

The hpx thrust will be stated as an exact figure when I can be absolutely damn certain AND independently verified, till then I wont put any definite figure on my website. Thats just the way I operate.

No, I wrote before that I ran it for 5 minutes on kerosene, and established an approximate 450ml per minute, not with propane, I really only got 1 minute of solid calibrated test of that, so when I get some more time I will know more.

As for thrust, can anyone really be "Exact" without having frictionless bearing systems designed specifically for PJ use? I do the best I can with what limited materials I have. The HPX-30 has still got a few mods to go yet, I wont be posting "Exact" figures till all the mods are complete.

Right now I'm up to the testing stage E-5 Model of the small hpx, (7 models of the HPX all up Including 1 and 1b), small steps CG, but they get you there.

[CG]

small steps CG, but they get you there.

You're right, and you would know about this stuff, not me! I was just curious about the numbers. Thanks for clearing that all up!
Very innovative work you're doing, keep it up!

[gettylee]

Hi,my name is Brian.I've built a fwe & hpx engines,that path will run on 14 oz propane,but tank freezes up,I've been trying methanol,but getting ossolateing thrust pulses,mabey a pressure,or injector prob.? Side love to try a rc plane. Can anyone help?thanks much, Brian PS. I've been using my fwe for expimenting&than want yo switch to the hpx for possible flight?:)

[gettylee]

Hello,my name is Brian,I built a hpx scaled same as my fwe w/7.44" combustion chambers,that both run on 14oz lp tank,but freeze up at half a tank,im trying a homemade bladder system on methanol,but the pitch ossolates&won't sustain on just methanol,I would love to build a rc plane with s hpx valveless.suggestions will be much appreciated!!! Thx,Brian

[John Hasler]

Where can I find drawings for the HPX?

[gettylee]

Where can I find drawings for the HPX?

I've got a drawing with the dimentions of the hpx that I built.although, it was a very rudimentary way I scaled it,may not be perfect,but it works!

[gettylee]

Here are the dimensions of my hpx.It is a strong runner!