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All Forums >> RC Airplanes >> RC Warbirds and Warplanes >> Learn to fly 60 sized warbird
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Learn to fly 60 sized warbird - 6/4/2002 12:53:01 AM   
onewingtoolow



Posts: 30
Joined: 4/9/2002
From: Houston, Texas
Status: offline 		I am currently flying a 40 sized P51 with a Saito 72 engine. As the same time, I have a Model Tech 60 sized P51 under construction. The Model Tech P51 has a 66" wingspan and is equipped with robart retracts, flaps, and an OS 120 for power. It will weight about 10 pounds.

I am trying to learn as much as I can with my 40 sized P51. I try to fly the 40 sized P51 like a real warbird: build up engough spped before taking off, maintain enough air speed, make gentle turns, land with some speed, etc. One thing I can not do with my 40 sized warbird is using flaps for landing.

Is it a good idea to install flaps on my 40 sized P51? I have proper building skill to add flaps. Is it good idea to add more weight to my 40 sized P51 so it will have a wing loading similar to the 60 sized P51?

In terms of flying characteristics, what are the major differences between the 40 sized and the 60 sized warbirds?

Your advice will be appreciated.
       Post #: 1

Learn to fly 60 sized warbird - 6/4/2002 6:59:16 AM   
bmustang


 

Posts: 96
Joined: 1/31/2002
From: Nassau, NY, USA
Status: offline 		1wing, you are off to a very good start. I had a Model Tech P51 that I made some extensive modifications to for better scale appearance and to change it to a P51B. I used a Super Tiger 90 and it flew very nicely at 10 lbs 6 oz. One thing, the wooden beam mounts for the engine were far to weakly attached to the fuselage. The vibration loosened them in only 3 flights. I filled in the spaces between the beams and the fuselage sides with some scrap hardwood I had around the house, both in front of and behind the so-called firewall and also added a piece between the beams behind the engine. Then I drilled and dowel pegged all these together - the fuselage side, filler piece, and beam on each side in 3 places (one going into that cross piece) and also 2 more pegs going thru the nose ring into the forward ends of the beams.
No more loosening.

The balance point called for in the instruction book seemed ridiculously far forward compared to other Mustangs, so I calculated my own 25% MAC and used that, and it worked fine. The model still had a tendency to go on its nose when landing, and I ended up adding some tailweight. Tried some tight loops and got no snapping, so the CG worked ok even farther back than where I started.

The flaps on this model were wonderful - I got no trim change at all when deploying them, and they really greatly improved landings and also made them much shorter. It may not be worth the trouble to install flaps on your 40 Mustang, unless you really want to do it. When you test fly your Model Tech, just land without flaps until you get a chance to go up high and try them to see what happens on yours.

I used separate servos, one for each flap, but there is a down side to doing this. If one servo fails and only one flap goes down, it will try to roll the airplane and you may not recognize immediately what the problem is. (Opposite aileron and put the flaps back up as fast as you can.)

A picture of this model is in Frank Tiano's column in the March '02 RC Report magazine. p 53.

Although I had some issues with the structural design and the inaccurate scale outline out of the box, this model does fly very well.

Good luck with yours.

Tom

(in reply to onewingtoolow)
       Post #: 2

Learn to fly 60 sized warbird - 6/4/2002 6:45:33 PM   
onewingtoolow



Posts: 30
Joined: 4/9/2002
From: Houston, Texas
Status: offline 		Tom,

Thank you very much for the info on the Model Tech P51 engine mounting beams. I will do what you did to yours.

I still have a copy of the March issue RC Report. Your Model Tech P51 looks great. Converting to Mode B is a great idea. It is unique, and it stands out from the P51 crowd. In fact, that picture triggered my decision to buy the Model Tech P51.

As a relatively new RC flyer, I have some difficulties following the way you explained how you set your CG. Can you explain it in more detail?

Thanks.

One Wing

(in reply to onewingtoolow)
       Post #: 3

Learn to fly 60 sized warbird - 6/5/2002 8:43:53 AM   
bmustang


 

Posts: 96
Joined: 1/31/2002
From: Nassau, NY, USA
Status: offline 		One wing, I wish I could remember the exact dimension I came up with for my balance point. I'll hunt around the house and see if I can find the paper I did it on. There is a graphical solution and if I could draw a diagram here you could follow it easily, but it's going to be harder to describe it in just words. I made a drawing of one wing panel scaled down to a convenient size on a sheet of paper. I ignored the leading edge "crank" and extended the LE and TE lines to where they would intersect the fuselage center line. THen measured the chord at the center line and the chord at the tip. Extend the tip chord line both forward and backward each by an amount equal to the center chord, and do the same at the center chord extending forward and backward by an amount equal to the tip chord. Now you draw a big "X": draw one diagonal line from the forwardmost point on your extended tip chord line to the rearmost point on the extended center chord line. Then the other diagonal from the forwardmost point on the extended center line to the rearmost point of the extended tip line. Where these two diagonals intersect is the location of the Mean Aerodynamic Chord line on the wing. Draw the chord line at that point on the wing diagram. Measure 25% or 27% back from the LE on that line and that is your balance point. 27% MAC is a good safe starting point for balancing most conventionally designed airplanes.

Don't go by my airplane as an example of how a Model Tech Mustang looks - it doesn't look like that out of the box! The fuselage is an inch and a half too short behind the wing, the vertical tail is too small and the wrong shape, and the horizontal tail is also the wrong shape. At least the company corrected the "skinny nose and pointy spinner" monstrosity that was shown in the pictures in the ads. A 4" parabolic (P51) spinner is correct for this model. I used a CB associates red one, and if I were doing it now I would use a metal one from Dave Brown Products.

Tom

(in reply to onewingtoolow)
       Post #: 4

Model Tech Mustang - 6/5/2002 9:36:35 AM   
JET FX



Posts: 1527
Joined: 1/20/2002
From: Sydney, , AUSTRALIA
Status: online 		I have built and flown 2 of them. Still have one, they are a great flying models much eaiser to fly than the 40 size models. I scaled mine out with Top Flite P51D 60 size canopy, spinner and static 4 blade prop, chrome monokote. I would suggest a servo on each aileron, leave single servo for flaps. Use Robart oleo struts to dampen landings, put larger Robart 3 1/2" scale wheels on it this helps avoid nose overs and is much more scale looking... I flew mine with both a O.S.91 Surpass FS and a Y.S. 91 with 16x6 prop. The Y.S. is perfect, and sounds just right. As the unpumped O.S. running inverted can cause problems eg hydraulic lock and plug flooding at prolonged idle/ landing approach!!!
Engine cooling- open up the exhaust ports, also I added three holes the size of nickels at rear of cowl underside to get the hot air out. Never had a problem with cooling!
Landing, I found best to drop full flaps just before turning onto base leg and do a steep curved fighter approach, carring 1/3 throttle till just before threshold, then let her settle in... I could not land with out flaps and not nose over (on grass)
They look awesome on those fast straffing runs... Heres a couple of pics of my two

cheers - Marty

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< Message edited by ozcan -- Jun 5 2002 5:02AM >

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JET FX Australia~ Cosmic Pilots, Jets Munt, Yellow Aircraft, Sis-T, Fei Bao, Fly Eagle Jet, Wren- www.jetfx.net

(in reply to onewingtoolow)
       Post #: 5

P51 pic - 6/5/2002 9:38:55 AM   
JET FX



Posts: 1527
Joined: 1/20/2002
From: Sydney, , AUSTRALIA
Status: online 		'Ridge Runner'

Question? are the model tech 51's still for sale any where? I would like to do one up as Red Baron- Reno racer...

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       Post #: 6

Ridge Runner - 6/5/2002 9:47:16 AM   
JET FX



Posts: 1527
Joined: 1/20/2002
From: Sydney, , AUSTRALIA
Status: online 		And another angle.

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JET FX Australia~ Cosmic Pilots, Jets Munt, Yellow Aircraft, Sis-T, Fei Bao, Fly Eagle Jet, Wren- www.jetfx.net

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       Post #: 7

Model Tech P51 - 6/5/2002 6:54:44 PM   
onewingtoolow



Posts: 30
Joined: 4/9/2002
From: Houston, Texas
Status: offline 		Tom,

Your instruction is very clear. I can follow it quite well. I guess sometimes there is benefit of being a boring engineer like myself. I will use this CG as a starting point and have an experienced warbird pilot in our club to perform the maiden flight. Thanks.

Ozcan,

I bought my Model Tech 60 size P51 from my LHS here in Houston. It does not look like Model Tech is selling it anymore. I will ask my LHS about this. Thanks.

One Wing

(in reply to onewingtoolow)
       Post #: 8

Ozan - 6/6/2002 7:10:50 PM   
Carlos Murphy


 

Posts: 1366
Joined: 12/27/2001
From: Gardnerville, NV, USA
Status: offline 		Global is the distributer for Model Tech.
[url]www.globalhobby.com[/url]

(in reply to onewingtoolow)
       Post #: 9

NO 60 size P51 ?????? - 6/7/2002 2:03:16 AM   
JET FX



Posts: 1527
Joined: 1/20/2002
From: Sydney, , AUSTRALIA
Status: online 		Thanks Carlos for the link to Global. I just checked it out, it appears they have stopped selling the 60 size P51? Aint it always the way....
Pity it is as close to scale out line as any ARF of its size, that I know of.....

I will just have to extra careful with 'Ridge Runner' I guess : )

Cheers - Marty

_____________________________

JET FX Australia~ Cosmic Pilots, Jets Munt, Yellow Aircraft, Sis-T, Fei Bao, Fly Eagle Jet, Wren- www.jetfx.net

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       Post #: 10

Oscan - 6/7/2002 8:07:51 AM   
Carlos Murphy


 

Posts: 1366
Joined: 12/27/2001
From: Gardnerville, NV, USA
Status: offline 		Which kit is your Ridge Runner?

I'm working on the World virsion, am in the process of installing "Frank Tiano" drop tanks with the large releases and mini servos. Total of 14 servos in the plane...

(in reply to onewingtoolow)
       Post #: 11

Which kit? - 6/7/2002 8:34:54 AM   
JET FX



Posts: 1527
Joined: 1/20/2002
From: Sydney, , AUSTRALIA
Status: online 		Carlos, my P51 is the Model Tech 60 size kit. I bought the kits in Australia four years ago. I have since moved to Canada so do not know if they are available here in Canada, I pressume not as I have not seen any? and it looks like they are no longer available in the U.S. either? I could probably bring one back from Oz on my next trip there! but freight costs would be high making it not worth the effort. I think I will save some more pennys and get a bigger one anyway, I do like that Aerotech 1/5 scale P51.... maybe with a Y.S.140 in it : )

Cheers- Marty

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_____________________________

JET FX Australia~ Cosmic Pilots, Jets Munt, Yellow Aircraft, Sis-T, Fei Bao, Fly Eagle Jet, Wren- www.jetfx.net

(in reply to onewingtoolow)
       Post #: 12

Model Tech P51- How bad do you want one??? - 6/7/2002 8:52:23 AM   
JET FX



Posts: 1527
Joined: 1/20/2002
From: Sydney, , AUSTRALIA
Status: online 		O.K. guys, the good news! you can still get them... the bad news is you will have to get them mail order from Australia $228.55 U.S. + shipping (yikes) I can only imagine? probably add about $150 U.S. for shipping (just a guess)
That said $370 ish is not unreasonable for a ARF model of this size and quality. All depends how bad you want one? They are better than any other P51 -60 size ARF or should I say ARC. as far as scale outline goes. And with a bit of customizing can be made contest worthy....
heres the url to the Kellets hobbies in Sydney Australia where I bought my P51's- http://kellettshobbies.com/ieindex.html Kellets are a very well established store with a great reputation, one of the biggest hobbie stores in Sydney, and specialize in mail order. So if want one contact Gary Kellet the store proprietor he will look after you... Hope this helps if there is no other source in the U.S.

Cheers- Marty

< Message edited by ozcan -- Jun 7 2002 3:57AM >

_____________________________

JET FX Australia~ Cosmic Pilots, Jets Munt, Yellow Aircraft, Sis-T, Fei Bao, Fly Eagle Jet, Wren- www.jetfx.net

(in reply to onewingtoolow)
       Post #: 13