the priority to fix bugs is based on votes. only 21 votes for this bug. it will not be fixed any time soon unfortunately 
Although Iād certainly like more votes on this topic, itās not purely based on number of votes.
In fact, about two and half months ago, as Jummivana said, they worked on this bug and apparently at the time thought they had a fix. Unfortunately, whatever they did to fix it didnāt work. And instead of continuing to work on getting an immediate patch out - which is what youād assume would happen with a payware aircraft - it appears like theyāre only attempting to push fixes for this during SU releases. So now we wait until the next SU. And if its not fixed by then, well you know the routine. And that makes me 
.
I know sometimes warbirds can sit non-airworthy for many months at a time but this is too much simulation for me. 
Do you have the same issue if you follow the OPās steps to reproduce it?
Yes. I purchased RENO AIR RACES: EXPANSION PACK today.
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I tried letting the AI control it, but it stopped in the same way.
Add information about engine RPM.
Before takeoff, it will stop if it exceeds 2900 rpm.
After takeoff, it will stop if it exceeds 3000 rpm. I was able to fly for over 30 minutes as long as I didnāt exceed 3000 rpm.
Are you using DX11 or DX12?
DX12
Are you using DLSS?
No
If relevant, provide additional screenshots/video:
Do you have the same issue if you follow the OPās steps to reproduce it?
Yes
Provide extra information to complete the original description of the issue:
Reno P-51s will not take off. Engine fails even at low throttle
Are you using DX11 or DX12?
DX11
Are you using DLSS?
No
If relevant, provide additional screenshots/video:
Last year, I bought several of the Reno P-51ās before I realized there was a ābaseā one which is the one used for repaints. Aside from lacking autopilot and weird fuel flow where the right tank will drain down into the left (Iām guessing this is related to it being a race version and is actually semi-realistic?), the model looked great, the sounds were good, and the aircraft flew reasonably well for touring.
This weekend I took it out for a flight around the new Thorpe Abbotts WW2 scenery, and was dismayed to discover the plane is unflyable. The engine barely wants to start and keep running, and when it does, it dies shortly after takeoff. I spent over an hour trying different things thinking I was doing something wrong. Best case, I could climb perhaps a couple hundred feet before the engine died. Worst case, it would die on the ground before I even taxied to the runway. I tried both cold and dark (how I normally do things) and hot starts on the runway.
Then I found this thread and realized I had just wasted my time on a borked add-on from Micro$obo. So Iāve spent a decent amount of money on a product line that hasnāt worked for how many months? This is highly disappointing, and frankly unacceptable.
Do you have the same issue if you follow the OPās steps to reproduce it?
Yes, same issue. Engines wonāt run on P51 Mustang Unlimited Class.
Provide extra information to complete the original description of the issue:
I purchased the Reno pack day one, Release day. Everything worked great. The BiPlane Class, the T6 Class had no issues I can recall. The Unlimited class had some issues like pitch indicators being offset in their āwindowā and interiors popping through the exterior model when zooming at certain angles with the exterior cam. As well the P51 would run out of fuel and when selecting a new fuel tank the engine would die. Even after an in air restart with fuel pump, the engine would die. This happened so much I just mapped a āfull fuelā button on my HOTAS.
Recently I tried the P51s and they wonāt run at all. Following starting procedures, which Iāve done many times in the past. Engine will start, and if I tap the throttle up; the engine instantly dies out. Even starting airborne, the engine dies out with a bump of throttle. I donāt have any conflicting throttle options, as my Setup works great with other planes, even the T6 class. Somewhere along the line a bug was introduced.
I did have major update issues with the Reno pack downloading and stalling, restarting and quitting. I canāt remember if that was SU13 or before. When we first had the content manager/sever download speed issue arise.
Are you using DX11 or DX12?
Xbox Series X
Are you using DLSS?
Xbox Series X
If relevant, provide additional screenshots/video:
Do you have the same issue if you follow the OPās steps to reproduce it?
YES
Provide extra information to complete the original description of the issue:
HOW IS THIS STILL BROKEN?!?!?!?!?!?! This Is Official PAID content that is fully unflyable.
Are you using DX11 or DX12?
12
Are you using DLSS?
Yes
If relevant, provide additional screenshots/video:
Iām having the same engine stall issue when opening the throttle. Has anyone else noticed that on the tank selector, you canāt select āMain Tank L.H.ā or āMain Tank R.H.ā? I can only select the other 3 positions. The weight and balance applet shows fuel in all tanks. Is there something I donāt understand about the P-51ās fuel system?
Iām answering this having played around with āBunnyā just now. They messed up the graphic (unless the real race plane was rewired, which is possible), so that when you select right hand (the left side) drop tank, it uses fuel from the left hand main tank and vice versa. You cannot select main tanks (which should be drop) because the plane cannot have drop tanks. Personally Iād just throw the switch left, ignore the fine print and use fuel from the left tank etc.
However it still has the issue where the engine dies when fuel flow reaches a certain point. If you lower the RPM, you can push manifold pressure higher, but in no circumstance can you run the engine up to anything close to maximum power without it dying.
On top of that, the oil presure, fuel pressure and temp guages do not work.
I canāt tell if the fuel boost pump actually does anything because the pressure gauge doesnāt work. Turn it on, turn it off, nothing mattersā¦ UNLESSā¦ you switch tanks while itās on. If you do that, then turn it off the engine dies. Switch tanks w/o it on and youāre good.
Itās really sad that they made such a mess of these. Itās even more sad that the only other P-51 Iām aware of is made by Aeroplane Heaven and while it works better than these, itās still not worth what they ask.
Compounding the issue, from everything I see, it does appear these P51ās all have their own problems which will be a headache to fix Iām sure - and probably why theyāre still a hot mess.
okay, thanks for your clarification. At least that makes sense about the 3 positions. I was hoping the problem was that it defaulted to a drop tank that wasnāt there, but as the title of this topic says, even selecting the fus tank doesnāt help. Itās really frustrating because I want to fly a mustang badly. Now I have 2 of the MS P-51s that donāt work and I just sprang for the AH P-51 and it shows in the Content Manager (as Uninstalled / Community) but nowhere to be seen in the world map 
The AH Mustang isnāt the worst plane in the world, but compared to Flying Ironās fighters, itās not great. Nevertheless, it does work. My biggest complaint about it is that the wind sound is very loud. Way too loud.
It wasnāt long ago some of these Mustangās worked pretty decently from the Reno pack. I was in the process of testing them for actual performance, range, etc because the in game stats were obviously way off. Iāll try to fiddle with the rest soon. Maybe thereāes ONE that isnāt brokenā¦
Do you have the same issue if you follow the OPās steps to reproduce it?
Yes.
Provide extra information to complete the original description of the issue:
My specific experience is with the ābaseā P-51D of the Reno Expansion Pack. Currently, this product is completely unusable. The engine does not reliably start, and even when it does, it will cut out in short order. The furthest I was able to get before the engine quit was a few moments after takeoff. In the worst case, it quit while I was still parked on the ground.
I tried starting from cold and dark as well as āhotā - lined up on the runway. It was the same every time. I followed the procedure and tried to troubleshoot by limiting throttle/mixture/pitch, but the issue remained more or less constant. In its current state, this product is completely broken and unusable.
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I still donāt understand how is it possible that this bug isnāt fixed yet, and that is not so clear to the developers. The Reno pack is totally useless: p51 unusable, matching online totally useless/empty,no one do it. And I canāt even ask for a refund.
Iām not sure they know. Today Seedy was talking about Bunny in the Friday Fly-In stream. I canāt imagine theyād bring it up if they knew it wasnāt flyable. I would think someone who bought it would be pretty frustrated. They all worked back when I bought itā¦ finding them broken was a different kind of frustration. But theyāre not great soā¦ itās not like I was flying them anyway.
Iām having the same exact problem described as OP with the default P-51. The plane is not flyable to nearly the performance it should be able to be flown. You can barely get the manifold pressure above ambient pressure (30in) before the engine dies. The P-51 was rated to fly well above ambient pressure continuously, and at full open throttle for takeoff. At the moment, full throttle will kill the engine in about 10 seconds or less.
This engine limitations placard shows you military power at 61in is possible for 15 minutes, and that is completely impossible at the moment.
From this youtube video:
This topic has 76 (now 77) replies and is what appears to be biggest on the first page.
Iāve spent Ā£50 on the Reno pack and have never been able to fly the bloody things! Itās shocking that this is still a big and an issue.
They couldnāt have overlooked it as this post stands out like a sore thumb.
Get it sorted, or at the very least acknowledge it so we know itās being resolved or worked on.
Many thanks.
I would ask for a refund and explain that it doesnāt work if you only just purchased it.
I wouldnāt be too optimistic in this case. Not a single soul at microsoft or Asobo cares for this issue, iām afraid, it will never be solved.
P-51s that have the bug at the moment:
F-51D Wee Willy II
P-51D Bunny
P-51D Mustang
P-51D Spam Can / Dolly
P-51D ManOāWar
All the other ones work fine.
How , where, ask it? Iāve tried to find a path to some customers service, but there isnāt any option for ādlc refundāā¦ Through steam, pc platform, you can ask a refund only for the entire game.