collectivepitch

My Feedback: (13)

i have a h9 Miss America p51 with a os 91 surpass. when taking off it wants to tip over on the nose if you ain't careful. is this he way they take off or do i have something out of wack?

Ram-bro

My Feedback: (101)

check your landing gear. do you have retracts? Either your cg is off or your gear is to far back of the leading edge.

kahloq

check your CG. Kinda sounds like your nose heavy. Normally, a P-51(and msot warbirds) will lift the tail up mostly level with the horizontal aspect of the plane as it moves down the runway when gaining speed. If its slightly nose heavy, it may over rotate a little bit, bit is not enough to cause a nose over. So, Im guessing your pretty nose heavy. Move the CG back in small increments(like 5mm, then 10mm if its still doing it)...BUT do not go further back then the CG listed in the manual.
You did check CG with the plane upside down and the wheels retracted and the fuel tank dry right?

collectivepitch

My Feedback: (13)

the manual lacks the proper cg instructions. it was suppose to be 4 3/4 in from the leading edge acording to the manual. a friend of mine help me cg it from the leading edge of the wing upside down and the gear in and i was less than 1 oz off. so we left it alone. the madien flight we notice it took alot of stick for inverted flight. so we fiquired it was alittle bit more nose heavy than 1oz. but he said the almost tip over was normal.

kahloq

The almost tip over is not normal. What do you mean less then 1 oz off? Depending on where that 1 oz is, it can make a plane act strangely. Did you mean 10mm off? Move the cg back a little and the nose over issue will go away.

collectivepitch

My Feedback: (13)

put a 3/4 oz piece of lead on the tail and it was level. was told is wasn't needed since it was so low.

kahloq

Uhh yeah...but level at what CG? The 4 3/4"? I have a friend with this same plane and he doesnt have this almost tip over problem at all....and the manual did list the proper cg.
You can either deal with the nose over problem, or adjust the cg rearward some from where you have it. Its obvious that its nose heavy and more so then just a little. The only other problem could be the wheels are not spinning freely.

collectivepitch

My Feedback: (13)

it was level at 4 3/4 with the 3/4oz of weight on the tail. i will shift the battery back some. the manual said 4 3/4 behind the leading edge of the wing. so i measured it from the leading edge of the wing beside the fuselage. thanks

frisconick

Or maybe just a bit too much power before you have any speed up on the ground?? My H9 Corsair will nose over if I give it too much throttle too early during takeoff.

Nick

Richard L.

My Feedback: (24)

That's pretty much normal with the H9 Mustang. It's a balancing act. Throttle/elevator management is key and will become second nature. I have my 16-oz tank on the CG, which helps during take off.

Rip n Bank

I'm "the friend with the same plane" and I agree with Kahloq that it shouldn't tip forward *significantly* on the take-off roll unless something is off.

1. Recheck the CG and make sure the plane balances level when upside down and supported 4-3/4" back from the leading edge of the wing measured along the fuselage. As you mentioned, relocate the battery to accomplish this, rather than adding dead weight.

2. Independent of CG verification, you should shim under the rear flange of the retracts so that the wheel's footprint is raked forward about 3/8" more when the gear is extended. I believe I accomplished this with a 3/32" plywood shim. Almost visually unnoticeable, this really helps resist nose-overs.

3. "Wheels spinning freely" is actually a valid concern. Recently, I've had problems with my Robart 609HD mechanical retracts not holding their alignment (preferrably a slight toe-in from straight ahead). Bottom line: they are worn out after about 70 flights! I'm replacing them with Robart 551RS at this time. No amount of tightening of the 609 strut set screw would hold one of them straight for long. When it rotates out of alignment, the toe-in becomes much more extreme, and that creates significant rolling resistance. The result: right when throttle is applied, and the plane accelerates down the runway lifting its tail, the fuselage just keeps rotating over the rolling resistance of the gear until the prop strikes. Check your toe-in and make sure the wheels rotate freely (and don't rub against the strut!).

All the above being said, when the gear IS aligned and the CG is properly set, the H9 60 'Stang still wants to slightly over-lift the tail as it accelerates down the runway. I typically counter this by giving it 4-5 "up-trims" on the elevator prior to take-off. After she's in the air and the gear is retracted, during climb-out I feed the same number of "down-trims" back into the elevator trim and proceed with the rest of the flight. If you forget, she'll tend to gradually climb until you remember!

Rip

Richard L.

My Feedback: (24)

Below are some videos showing me taking off my H9 Mustang. My CG is at 4.5" back from the LE next to the fuselage (4 - 3/4" is too far back).

* [link=http://www.warbirdobsession.com/h9_mustang/videos/take_off.wmv]Maiden Take Off[/link]
* [link=http://www.warbirdobsession.com/h9_mustang/videos/take_off03.wmv]Take Off #3[/link]
* [link=http://www.warbirdobsession.com/h9_mustang/videos/take_off04_scale.wmv]Take Off #4[/link]
* [link=http://www.warbirdobsession.com/h9_mustang/videos/take_off05.wmv]Take Off #5[/link]

It's all in the thumbs.

prop wash

It's throttle and elevator control on take off and landing.If you give full power on take off with very little roll out then you will nose over.Throttle up easy and hold up elevator untill you gain some speed then let the tail come up till you gain enough speed to lift off and rotate.This is common for most P51's.I know Richard L and I [many others too] have gone over this subject with other flyers before.So you are not alone in this.The war brds don't fly like trainers or 3Ders. Throttle and elevator is the key,and time on the sticks.Good luck.Tom
Outstanding flics Richard

77chickenhawk

sounds like a wheel toe issue. my spit will do that if the tires are toed in or out to much

skull1971

It's seem that the H9 P-51's like to tip over, on take off, and landing. Here's a question I didn't see and answer for in the above posts. Are you flying off of grass, or paved runway? That will make all the difference in the world, ya know drag on the wheels. Also have you checked the the wheels spin free? You'd be surprised how many planes are out there with wheels locked up, or close to it. Move the fuel tank to CG that, when full will transfer more weight to the tail. I'm no expert, BUT I did listen to Richard L. and did what he said, and my H9 P-51 is as sweet and any of my friends TF's or others.

P.S. I have a brand new H9 60 P-51 fuse if anybody needs one, just PM me.

collectivepitch

My Feedback: (13)

Thanks for all the replies!
i do fly off of a paved runway. i'm in the process of changing the retracts now to 609hd's. the stock ones where junk. i will add a shim under the rear of the retracts. once all of that is done i will move the battery back alittle to see what happens. this is my first warbird so i'm alittle cautious.

kahloq

before moving the battery a little, recheck CG with the new retracts installed. That may be all that is required to adjust the current CG since they are heavier as far as I know.

alcarafa

It 's all of the above comments or : 1- you joined the wings wrong and they have a banana shape ( one wing with wash-out and other with wash-in ) if your wings are ok, then you are pulling up with not enough take off speed, let the plane run full throt 'till it try to take off it self.

hope this helps.

regards.

Rafa

bigtim

My Feedback: (13)

I ended up making a batt/reciever tray for mine, so I could mount it about even with the CG or just slightly ahead to get the balance right,mine didn't come with one so I just built my own from some ply.
a couple of things I did was to coat the inside of cowl with a thin layer of epoxy,and use CA hinge material to reenforce where the screws attach the cowl to the fuse.
the cowl is a bit weak and my screws were reaming the holes out after just a few flights, the hinge material is tough enough so they won't do that.

I also used the tony howard exhaust stacks and ended up using Goop adhesive and the screws provided to secure them to the cowl.

I also added some sheet balsa to the inside of the fuse in the forward compartment where I would hold it durring start up, the sheeting was starting to break down with a little extra wood between the formers it seems to not be a problem anymore.

I also moved the tail wheel,to a more scale location, adding a little weight to the tail which helped getting the plane to balance out from all the extra I added to the cowl.
this plane likes a smooth run up to flying speed slowly adding throttle mine gets tempermental when I hit it hard,same goes for my H-9 P-40 they both like it easy on the gas durring the take off roll.
mine really flys well its one of my favorite planes.