Me-163 Fuel Burn Bug

[SmokinLoon]

They have changed their models based on supplied data in the past.

Seems to me that it is far and few between, if at all.  Has HTC ever some out and said "changing X to better model Y on said aircraft, thanks to So-n-So for presenting the data".  Anything as of late?  

I cant count the number of times people have presented concrete evidence that the current Mossie Mk6 has an incorrect speed model.  Remove the exhaust baffles that were present on less than %20 of the actual WWII Mossie FB MkIV that were used and let the plane perform as it should.  Likewise... there is supposedly a version of the George (perhpas the one we have) that allows 3/250kg bombs to be carried.  On and on...


      

[moot]

Seems to me that it is far and few between, if at all.  Has HTC ever some out and said "changing X to better model Y on said aircraft, thanks to So-n-So for presenting the data".  Anything as of late?  

I cant count the number of times people have presented concrete evidence that the current Mossie Mk6 has an incorrect speed model.  Remove the exhaust baffles that were present on less than %20 of the actual WWII Mossie FB MkIV that were used and let the plane perform as it should.  Likewise... there is supposedly a version of the George (perhpas the one we have) that allows 3/250kg bombs to be carried.  On and on...


      

Don't take this the wrong way, but have you only been around since this April?

Karnak,
     You will never see any data about speed vs engine efficency for the Me-163. The was never any reason to make data because its simply not a factor. Right now its a catch 22 because I dont know how to prove without a doubt with WW2 data. Other than math formulas based off hard data from the rocket engine itself I dont know what to do. Some input from HTC would be nice...

Steel

They dont respond to posts this quick on the forums. They usualy speak up if it's really necessary (e.g. they could have read this and have made a note about your point being accurate).. Your best bet might be to make your case as concisely as possible and either giving them a brief call, or emailing the math (on a clean and clear format like pdf or something) to e.g. Pyro.

[Bronk]

Yea they never fixed the 109.

[moot]

The Ki84 was altered and finished up for release pretty much at the last moment with help from someone in Japan supplying documents, IIRC. 

A good example, see Toad's posts for good guidelines.
http://bbs.hitechcreations.com/smf/index.php/topic,64443.0.html

[Motherland]

Seems to me that it is far and few between, if at all.  Has HTC ever some out and said "changing X to better model Y on said aircraft, thanks to So-n-So for presenting the data".  Anything as of late?  

I cant count the number of times people have presented concrete evidence that the current Mossie Mk6 has an incorrect speed model.  Remove the exhaust baffles that were present on less than %20 of the actual WWII Mossie FB MkIV that were used and let the plane perform as it should.  Likewise... there is supposedly a version of the George (perhpas the one we have) that allows 3/250kg bombs to be carried.  On and on...


      

Rather recently (2.12 or 2.13) they added a 200 rd option for the 20mm on the 109G6 and G14 when someone presented evidence that this load was available.
The Mossie's CoG was adjusted rather recently as well.

[TUXC]

The 163 never had any throttle control, it was either full, or dead. So, we could not possibly know what the fuel burn rate was for the 163, when it never had any throttle control to begin with.
<S>

Not true according to someone who actually flew them. It sounds like HTC got it right.

"The engines were completely throttleable."
and
"You had unrestricted throttle control from ground idle to flight idle to cruise power to full power."
-Rudy Opitz

http://homepage.ntlworld.com/andrew.walker6/komet/flight/flight1.htm
(quotes about engine throttle control are on pg. 2)

[Steel]

    They got it right to a point and no one is contesting the part-throttle capability. Indeed for the time an engine with such deep throttle capability was a technical feat. Engines do not like be operated of their nominal pressure. The big issue is the decreased fuel burn at high speeds. Without hard data about the engine parameters the math is merely an exercise.

Steel

[BaldEagl]

Not true according to someone who actually flew them. It sounds like HTC got it right.

"The engines were completely throttleable."
and
"You had unrestricted throttle control from ground idle to flight idle to cruise power to full power."
-Rudy Opitz

http://homepage.ntlworld.com/andrew.walker6/komet/flight/flight1.htm
(quotes about engine throttle control are on pg. 2)

Beat me to it.

[moot]

Steel dont get too impatient.. If the info is available, someone'll be along with it.
I guess you've seen this already?  http://en.wikipedia.org/wiki/Walter_HWK_109-509

http://www.walter-rockets.i12.com/walter/163.htm
http://www.walter-rockets.i12.com/design/design.htm

[whels]

http://bbs.hitechcreations.com/smf/index.php/topic,125124.0.html

Steel i posted about this in 2004 (above thread), you see how HT
paid attention to it then

the 163 GPH should not change, with speed. It should be constant for what ever
throttle setting you have it at no matter what speed your going.

[Steel]

Whels,
    While you brought it up it was not gone through in much detail and some of the few facts presented were false. The ME-163 was able to refire its engines in flight but it was not a normal procedure. In fact you only needed to supply fuel to the combustion chamber and they combustion process started itself. The GPH did not decrease as a function of fuel level. The fuel system comprised of two sets of pumps, a primary and a inducer pump. The inducer pump prevented cavitation in the primary pump by increasing the inlet pressure a small amount. The primary pump supplied the majority of the pressure to the combustion chamber. As long as the inlet to the pumps remained covered by the available propellant the the pressures were constant. As previously stated the altitude effects the thrust output by a small margin. Hopefully with a little explanation and some anecdotal evidence we can at least get thier attention.

Steel

[NHawk]

The 163 never had any throttle control, it was either full, or dead. So, we could not possibly know what the fuel burn rate was for the 163, when it never had any throttle control to begin with.
<S>

Nevermind...my reply was covered in page 2.

[moot]

Steel, it's easier for anyone who was the info you seek if you say what you need to know about the engine, specificaly, to make a bulletproof case for what needs to be changed.

[Steel]

    The thrust vs altitude is easy to show the relationship with a few formulae. Chamber pressure, thrust, and exit pressure or exit diameter are the critical functions. The thrust vs speed I cant show with math unfortunately. Quite simply the formulae don't exist because the relationship doesn't change. There is a formula for rocket nozzles operating a very high speed. So high in fact that the measurement of speed is measured in the percentage of lightspeed. We hardly approach anything like that in AH2 so its a conundrum....

Perhaps I can apply the formula just to show an example?

Edit: Even that only measures the time vs speed change from regular Earth time so no go.

Steel

[BoilerDown]

The OP makes a pretty convincing case, I would be interested in seeing a response from HiTech as to why the thrust changes as well.  Maybe there's a factor we're not considering, or maybe they just got it wrong.