ModelTech P-51D 60 RTC/ARC (out of production)

I acquired one of these out-of-production RTC models, and
have been assembling it up for a while now. These RTC models
must have not sold very well, because there is limited info
on the web or these forums about them. For this reason, I'm
creating a thread and I'm going to try and fill it with lots
of pictures and information. Hopefully the thread will be a
resource for folks who find themselves in the same position
as I was in: without a manual, and without much online guidance.

Very fortunately, there have been some discussions abou the CG.
Here are the most relevant threads that I have found on RCU:
http://www.rcuniverse.com/forum/m_16.../tm.htm#163239
http://www.rcuniverse.com/forum/m_24.../tm.htm#244925
http://www.rcuniverse.com/forum/m_21.../tm.htm#215371

I wasn't able to find a photo of the box cover, but some
product images are attached.

Attached are a few photos of the build up to where I am now.
Please let me know if I can answer any questions.

Notes:
- Robart 605 pneumatic retracts
- Saito FA-100 powerplant
- Top-Flite canopy used, modified to be removable.
- Servos installed in wing via extra mounting ribs

Update Photos: Engine Installation

Here you go...
http://www.rccanada.ca/bb/album_personal.php?user_id=60
Sorry for some reason I could not upload the pics here, but if your interested there two here in my RCC gallery that I built and modified in the late 90's first one 'Cripes A Mighty' flew great with an O.S. 91 4 stroke and second 'Ridge Runner' flew even better with a Y.S. 91 AC. I also used the T/F 'D' canopy as more scale profile and scale prop for static. Also sheeted tops of wings as it looks way better... flys great but have to get into habit of doing steep sweeping fighter style approach landings using full flap otherwise tends to float. I also found ground handling much better (less nose overs) when fitted with Robart oleos. One of the best looking mid size ARF P-51's with a little kit bashing the Hanger 9 version has no scale control surface counter balances...

Cheers- Marty

Thanks Jet, for sharing.

Any advice for the maiden flight? Do you use any bit of flaps for takeoff?

Re-maiden, well not much to be concerned about really long as CG is in recommended location, just standard warbird takeoff ie ease throttle on gradually while holding in some up elevator and a little right rudder, easing off elevator as speed builds. I used larger diameter props with finer pitch to take advantage of thrust over speed also and that seemed to work well.
Probably could take advantage of expo if your Tx has this? dial in approx 20-30% on rudder, elevator and aileron this saves having to use high/low rates. Another tip would be to use nice large scale wheels (Robart) which may mean opening wheel wells up a little, as this will help better for grass field ground handling..... oh yeah try with/without muffler as not much sound difference I find on many of the 4 strokes and looks much nicer without, just tap new pressure nipple into header. Dont forget to get used to flaps though as landing without I found always ended in nose over, not much pitch when lowered either, at least not enough to require re-trim and no flap required for take-off. Dont allow to slow up when landing to much as tip stall is visious so as I said in first post practice full flap steeper curved fighter approachs aiming for threshold before leveling out for flair, sounds trickier than it is once tried a couple of times and nice wheel landings will be easy. It flies pretty good and tracks well and lands predictably once you get used to it.
Top flight offer a scale profile static spinner also from memory. [8D]

Hey got my stang pics to upload[sm=thumbup.gif]

Thank you for going into so much detail. This will be my first Warbird flight.
Hopefully I've got enough tail-dragger experience with an Edge540, a Phaeton
Biplane, and a DragonLady to make it a successful experience.

I'm glad that you brought up the CG. I don't have the manual, but the first
thread that I listed above indicates that there is some degree of confusion
about where the CG should be. One part of the manual says 3.5 inches from
the LE at the center section, another says 4.25 inches. Which do you fly with,
and where do you measure it from? Perhaps from the notch in the leading edge?

Thanks again, mate. Your P-51s are real beauties

EDIT:
Do you really run your four-strokes without a muffler!?! That is incredibly interesting.
I've never heard of that before. Do you have a photo of the setup?

No worries, always more than happy to be able to assist where I can.... Main thing to remember with this and most warbirds is to not come up to fast on throttle during takeoff due to swing to left, if eased on rudder has chance to become fully effectly and will then be a breeze. Also the wingloading is higher than the models you have mentioned there so remember keep the speed up a little on landing approach. A tip stall with flaps deployed likely will be unrecoverable especially if during landing. Maybe good to get use to flaps up high and practice steep aproaches with reduced throttle, I didnot bother mucking around with various settings I just use max deployment approx 40 degree deployed mid to 2/3 down wind and curved steep approach as mentioned, it does not pick up much speed and easy to manage after little practice.

I dont recall CG from memory, but will check within a day or two and let you know as I do have it marked on model Iam sure, its been stored away for quite a few years and during two house moves now.
Re- 4 stroke mufflers I have found that on many 4 strokes the so called 'muffler' does not really offer significant noise reduction and internally some like O.S. and Y.S. have little in way of serious baffeling, they seem more ther for somewhere to attach tank pressure nipple. On my Y.S. I run simply without muffler or pressure nipple due to already pressurized fuel system and just attach a section of brass tube extension clamped to exhaust header nut. On the O.S. with its curved header I just remove muffler and drill/tap end above threaded section to add the same pressure nipple that was on muffler. The noise difference is not significant and infact has a slight bark to it... deffinetely more noise can be heard inflight coming from prop, thats why I go for larger diameter, finer pitch as they make less whine at lower RPM they spin at. I dont have any pics of the O.S. but heres the Y.S. set up the same but in a Acro Sport bipe.

Oh yeah I was meaning to ask why did'nt you mount engine inverted?

Cheers- Marty

Great post , thanks for the info . I have this new in box , like the look so I bought it when Hobby People /Hobby Shack was discontinuing the line .They said that the ARF market was evolveing into covered planes , (who would have thought lol) but as we all know they were so right .
I plan on useing flite skin on this plane in scale panel position with aluminum paint and robo struts . I will also add an interior kit , any plane with scale counter balances is worth the effort .

The Fliteskin would work great for re-skinning the wings.... Also when comes time to paint its worth considering covering fuz in either chrome Monokote or even Flite Metal! maybe even Aluminium duct tape would be good idea? I glassed my one prior to finishing. Remember the stang actually had painted silver doped wings during the war years to help fill rivets etc this was to aid aerodynamics of the laminer flow wing design, so only fuz and tail would need to have the bare metal finish and easy to use silver paint on wings and still be true to scale. The metal tape/ Monokote comes up a treat if grently scuffed using super fine steel wool... (direction of airflow on wings, and stabs, vertically on fuz and fin) hey go nuts and experiment with masking up individual panels and dusting with blue and brown artist pastels, this adds further to the illusion of different grade metal types found on the real thing.

Another mod I made was to improve scale outline was to sand round the squarish rear under side of fuz as much as practical and also add semi scale tailwheel gear doors. This model really kit bashes well into a decent looking scale warbird, of all the .60 size ARF warbirds I have ever seen its got to be one of the better ones. By the way approx 10 lb AUW can be expected, pretty good eh! The scale accessories and canopy available from the similar size Top Flite stang are all thats required for the transformation.
You could even go the next level and install a BBI 1/6 scale pilot which would look authentic. Heres a pic of my Vailly Hurri with a 1/6 scale BBI RAF pilot...

And some more pics I found of my MT stangs, you can see the exhaust of the O.S. 91 without muffler fitted, certainly makes for a clean looking install I reckon. Also opened up exhaust outlets and added some vent ing holes at rear underside of cowl, no cooling problems have been experienced what so ever. The inverted O.S. was not overly excited about prolonged idling and fast throttle transition, thats where the Y.S. shines! as can idle all day then slam throttle without a worry, that said the O.S. or even Saito when fitted with on-board glow set up should be then fine running inverted. I found the O.S. would only load up when at idle, flying is fine....

I didi some research its seems that mnay RCU members prefer ultracote aluminum as far as realistic iron on covering . I do like your suggestions , I will be doing a ton of mods , I have a Officers and a Gentlemen Pilot , very light weight in 1/6 scale , I will be purchasing the Top Flight parts for this plane and possibly an interior kit as a starting point

The Ultracote probably would be one of the better options if you want to go with quickest finish that resembles metal. The way I went was much more time consuming for sure... guess thats why I like certain ARF's as it allows me more time to spend on what I enjoy doing most, finishing and adding the scale detailing. Using the Chrome Monocote method requires glassing airframe with .75 oz glass cloth and epoxy resin then primer, marking out scale panel line position and cuttiing individual panels and covering.....these way adding rivet detail is also possible using brass tube in soldering iron method. If I was doing it again I would likely go with self adhesive aluminum duct tape method found in various width rolls at Home Depot, this is going to look better and be much cheaper $$ wise than Monokote or Ultracote option and its 'real aluminium'.

Re- pilots as long as you have one in there its all good eh![8D]

Cheers- Marty

Marty , I am with you , my favorite part is the finish and detail , I tried to upload some pics of my corsair but the computer is timing out . I have a question for you on the aluminum tape from home depo , how do you finish the plane before the tape and what about weight ?

heres some pics of my H9 corsair , plane flys great , canopy slides, gear doors , cj retracts , panel lines ect

Re- finish, I use glass cloth and epoxy resin followed by light coat of two pack auto primer prior to laying out panel lines with ruler and pencil. Of course it goes without saying the preparation time during this phase is a little time consuming, same as any decent paint finish I reckon, lots of sanding using progressively finer grades of paper upto 1500 wet and dry. You should end up with a shiney scratch free base surface prior to drawing on panel lines as the guide prior to application of metal tape... Flite Metal offer larger width self adheasive aluminum if the duct tape is not wide enough. On the MT-P51 and many similar scale warbirds the wide aluminium duct tape should do the trick though. On the wings that will be paint finished, where the panel lines are marked out in pencil I use a fine jewlers file edge and gently go over pencil line to create the panel lines in the primer. Its important to use a quality two pack primer, you can get this from auto paint suppliers, brands names vary regionally so just tell your local 'expert' paint guy that you want to paint over epoxy fiberglass as this once cured sands easy without clogging paper fills scratches etc and also will not lift during later top coat and insignia masking....
Oh yeah one important last paint tip Iam using a low pressure/high volume auto spray touch up gun and air compressor, approx 30 psi max for spraying, you should let your paint guy what gear you painting with ideally, so he supplies the right paint weather primers or colour top coat. I also use Humbrol hobby enamels and airbrush for weathering which go over auto primer well. Leave clear coat till last as flats are easier to spray and cover better. If you want a gloss or matt finish apply last in 3-4 fine dust coats.... easy eh! ; )

If I recall correctly AUW was 10.5 lb for my Ridge Runner with the glassed, metal finish and Y.S. 91 fitted... you would have to be pretty heavy handed with the glass and paint to be over 11 lb AUW and thats well within reason considering model size and wing area for the MT - P51.

Cheers- Marty

LDM, Very cool Corsair you have there... have you tried the fine steel wool weathering trick??? it gives a true painted metal effect.
I described method in earlier post.

I forgot to mention after primer is applied prior to colour coat spray some Humbrol or similar aluminum colour around wing roots and panel access areas as once top colour coats dry you can gently rub over with 1800-2000 wet and dry (used wet) and viola warn metal effect comes through, looks awesome and no way will you get the same effect with a brush and dabbed on silver paint!

Cheers-

RE- MT P-51 CG, I have been flying my two at 3- 1/2" measured from wing leading edge and center of wing panel joint. I have heard that others maybe flying as far back as 4- 4 1/2" 'for me' 3- 1/2" seemed fine.

Cheers- Marty

Hi Marty thanks for the compliment , no I have not tried the steel wool process yet , I have read about it and would like to try it .
I am looking forward to building this plane

Well fellas,

The maiden flight was performed last night with mixed results. The Modeltech
P-51D is a real sweetheart. Ground handling was a little dicey on the grass field,
even with the retracts angled forward about 15 degrees. I had to be very slow
on the throttle-up, but after the tailwheel came up, the take-off was quite like any
other tail dragger. She performed beautifully in the air, flying very stable and
predictably. Fly-bys were awesome, although they weren't quite as fast as I had
hoped. There are still a number of things I can still do to boost the top speed
though. Stall-tests revealed no tendency for tip-stall, and the airplane can fly
very slow with flaps extended. I spent a lot of time worrying about my first
warbird flight, but it was really quite easy to fly this plane.

The landing approach went quite well until I chopped the throttle prematurely.
I made an error in my depth-perception to where the plane was over the runway.
At one end of my flying field, the grass suddenly ramps up about 3' from the
level surface. I thought the plane was drifting just over this plateau area when
I cut throttle, estmating the wheels were about 6 inches above the grass.
In fact, the plane was not above this hill yet, and to my very unpleasant suprise,
the plane dropped a whole 3 feet, collapsing the left strut. It was a real bummer
of an ending to an otherwise incredibly successful flight. Fortunately, the damage
is quite minimal and it should be easy to fix. The real shame was that I couldn't
get more flights in before this happened. Just the one. The airplane really slowed
down nicely for the landing approach, and I know that I would have aced the
landing if the confusion over this hill didn't complicate things. I'm certainly not
going to touch down in that area of the field again. I'll go around for another
approach. Another lesson learned the hard way, I guess.

All-in-all, I feel quite good about the outcome of the maiden flight. This is the first
warbird that I have built and flown, and things could have gone much worse.

By some incredible luck, an ameteur photographer happened to stop by the field
(he's a club member) and wanted to photograph my aircraft in flight to try his new
digital SLR camera! The photographs are spectacular, so I've posted alot of them.

Note: I flew with the CG at about 4.25" back from the wing centerline LE.
The aircraft was plenty docile in the air with this setting, so I'm going to slowly
move it backwards to improve ground handling on my grass field. I would say
that 4.25" is a safe place to start with this model.

Did we tell you that we now dislike you for having suc a great RC field with an incredibale view !!!![:-]Just kiding but really man that is one great looking field

Congrats on the maiden , plane looks great , I am sure you will have it up in no time

Yeah, it's a very pleasant place to spend an afternoon. It's in Nothern Utah's Wasatch
valley, very near the Great Salt Lake. Lots of neat wildlife can be seen out there. The
club is called Wasatch Aero Modellers. The field is great for noobs like me because it's
bigger than a football field.


I fixed the broken retract. Details of the repair are available at this thread.
http://www.rcuniverse.com/forum/m_6066083/tm.htm

I'm bumping the thread after a couple years. Information can be hard to find for this kit, so I wanted to post a link to another source of info for potential builders of this kit. I refurbished my plane and added lots of new scale details, with progress updated in the thread below.

http://www.rcgroups.com/forums/showthread.php?t=1094964

This really is a great ARC if you can get ahold of one. They're getting rare anymore. The only drawback it the weak retract mounts that need strengthening.

Great looking plane!! Looks like the last two or three years have been good to it.

Brian

ya , really nice job