asphalt252

My Feedback: (5)

Bull,
I think the 1/7 Top flight Mustang always comes out tail heavy anyway. So moving your fuel tank back to the CG location makes no sense to me at all. You will need all the weight up front you can get and still may need to add more like lead. Tip I like to use a large cell pack 1800mah or larger these packs are big and heavy. Better to have useful weight than dead weight, oh put an on-board glow system on it the Ram unit is just great.

asphalt252

My Feedback: (5)

ticketec
The strut does not hit the under side top and I did not lower mine like I'm telling you all to do. This is why I'm having so much trouble with my doors hindsight is 20/20 if I only new then what I know now. One day I'll cut the rails out and lower them down into the wing more. As you can see by my retract mount it is flush with the sheeting yours should be a 1/8" lower so the doors will cover it when shut. I hope I'm explaining this well enough it is difficult to describe what you need to do to get it right.

bull51

Well, that makes snense then. I have to tell you, I just checked all the joints I glued with the aliphatic resing today. The sheeting looks good, but the fuse, I'm not to sure the joint is strong enough. Did you use aliphatic here or something else. I have read that it doesn't matter which glue one uses because if one crashes, one is normally left with a pile of toothpicks with the seams still in tact.

asphalt252

My Feedback: (5)

Bull,
If you can figure out how to make an airframe crash proof let me know and we'll both be rich! Aliphatic glue is much stronger than any glue due to its slow cure rate. It will soak into the wood fibers more to ensure a bond strength that goes far past the seam itself thus providing a superior joint. It also has many more advantages for our needs. Its dried composition has a similar density to the balsa wood itself so it tends to sand better. And of course it is not as hazardous to breath as CA or as heavy as Epoxy.

asphalt252

My Feedback: (5)

Ok guys I put her on the balancer today and this is what I got the first time out. Now my question to you all is just how much nose down do you think we need here? I think the sink rate of this baby will be quick not much of a floater here at all so I thought I would keep her balanced level. Most of my planes I like about 1 or 2 degrees nose down so when you chop that throttle she drops her nose and comes home. No worries with that here most Mustangs tend to fly on the prop anyway so make sure that engine runs good. But tell me what you think anyway. I’m ready to go just waiting for the perfect day! Notice how I used that great planes balancer clamped to my bench so I could get it farther (18" center to center) apart to balance it where the book said. Always balance a low wing plane upside down this puts the pendulum or fuselage of the plane down to stabilize it while balancing her. The pic below are hands off totally balanced as if she was flying level right on the CG.
Sorry about the mess working on another project.

ticketec

My Feedback: (2)

opps, that's what happens when there are 20 pages to go back through to work out who said what!

I guess you guy's (which ever country is least offensive ) might call me an Aircraft Maintenance engineer.......

Asphalt252,

Thanks for letting us learn from your mistakes. This is good news for me because there is now a glimmer of hope that i might get it to work for me. I will check out my radio manual because i was thinking of using a servo on the inner doors and sequence that with the radio. I know that i could get pneumatic cylinders designed specifically to do this job but i'm not sure how pricy they would be and how many cylinders can i operate of the one tank/system....

As for your nose weight, i pesonnally like the model to be pitch neutral. Because when doing aerobatics, they can come out ugly if she has a tendancy to drop the nose. I don't like the aircraft doing something i haven't commanded. Just my personal flying taste though. From what i have read on the P-51 and seen (T/F P-40) the flaps work like a big hand brake, and i'm not sure on this model, but most have a pitch up/down tendancy depending on design.

Thanks

bull51

Asphalt,

I'll work on that crash proof fuse, just don't hold your breath . Like I said earlier in this post, this is only my second kit build and the first was a Tower Fun 51which, called for epoxy only. I'm a newbie to kit building, infact I consider myself a newbie RC aircraft. Weight is not an issue with the kit. Up until I bought my u-can-do electric and started this project, I wasn't concerned about weight. I guess you can say the profile 51 spoiled me. She's a rocket and spins like a top.

thanks for the input,



ticketec,

I have read, somewhere in RCU, that this model will do all three of the following: some reported pitch up, some reported pitch down and then some with no reaction to the activation of the flaps. Not really sure that helps any of us, but just a little info if have gined here.

jamie_duff

Ticketec - if you look at the Top Flite Seafury build on this forum you'll find pics of someone's Seafury with servo operated gear doors. I like that setup and intend to copy it to some extent [8D]

I spent all afternoon scribbling all over my fuse plans and parts

So far, I've scrapped nearly all the ply formers and replaced them with 3/16" balsa. I've cut the fuselage crutch in half just forward of the F6 positionm and I've ditched F6 and F7.

F8 has been replaced with balsa with a ply doubler at the wing dowels. F10 is still ply as it mounts my tailwheel, and F11 is balsa. F3 and F8 have modified holes and there are small hardwood blocks attached to the formers just just below the top of the ply doubler. These are for screws which secure a 1/64" ply false floor which runs from the firewall right back to the radiator exit. This leaves a trough for my cooling air to pass through a (to be) fuel proofed fuselage. The false floor is removable for access and serviceability. The Elevator & rudder servo sit slightly rearward of their designed positions on a modified light ply plate. Next to them is the air cylinder for the tail wheel courtesy of Asphalt. The throttle servo is in front of F5 on the port side (thats where the carb is on the RCV 120SP engine) There is room to slide the tank in still........... fingers crossed.

All this leaves me space for a near scale cockpit (slightly shallow due to false floor) but I doubt anyone will notice. (If they do I'll thump them lol).

The CJM air reservoir cylinder fits inside the port inner wing just fwd of the flap servo hatch and the retract micro servos, sequencer and valve are inside the wing too.

That everything?? Phew........... hard work this thinking stuff. Tomorrow I'll start assembling all this and post up some pics if anyone is curious. Since I'm straying from the plans I'd appreciate someone to stop me before I make a big goof too!!! Got to tidy up the kitchen now as the wife is making dinner.............. Later folks........

bull51

Boy oh boy, jamie, that sure is a lot. What's the reason for replacing most of the formers, weight? I would most definately be interested in pics. I'm getting ready to start my fuse soon.


Asphalt,

Well, I've just proven, to myself, that I can read something a dozen times and still get it wrong. I was intending on sheeting the top of the wing today. Before I did, I went back a few pages and re-read the advise you gave me for sheeting the wing. Hhhhmmmm...after that I read the directions again. Turns out, I built my sheeting wrong. Not a big deal, as a matter of fact it really does not make a difference. What I did is only glue two sheets together instead of four. Like I said not a big deal, just reminding me to check the directions 13 times instead of 12.

ticketec

My Feedback: (2)

Hey Jamie,

I checked it out, Great! exactly what i wanted to do. I'll have to keep my eye on that thread too.

Please provide pic's because i'm keen to see what your doing. Is it for as bull51 asked weight reduction or is it so that you can put a cockpit in? I am aiming to also put a cockpit in so your work will be very informational.

For strength, i wonder what the weight difference would be of a ply former to a balsa one with .5 or .75oz glass on it? I reckon the glassed option would be lighter and stronger....

Thanks

jamie_duff

Hi guys.

First of all - no pics yet. I ended up taking my T-Bolt apart instead of putting the Mustang together!!! Doh!

Second - I am indeed putting a full cockpit in (it's about 3/4" shallower than scale though due to the cooling duct). I'm replacing the formers with balsa mainly for weight reasons, but also since the formers are being modified and the die cut holes are more a hinderance than a help.

I'll get on to it tomorrow though and hopefully will get some pics up

bull51

Hey all,

Finally got to the wing today. Sheeted the top. Hopefully everything comes out O.K. Had a hard time getting the sheeting to stay down on the LE of the ribs. I treid taping them down, but the sheeting was a little lower than the LE. Finally I used T pins and all went well, I think. Next time I might leave the LE off, that will make it easier to hold the sheeting down with just some masking tape.

ticketec

My Feedback: (2)

I still have a 2-4 week wait to get my kit... this is killing me.

bull51

Wow, thats long. Where did you order it from?

ticketec

My Feedback: (2)

I won it on ebay. I was after one of the commemorative editions that could be built as either a B or D version. i'm still not sure which version i will go with. To have it shipped to me in about 1 week would have been $91 USD. Tower hobbies wanted $120 USD. thats almost the cost of the kit. I ended up pay $50 USD but have to sit tight and wait....

bull51

Well, that explains it. I would sit and wait too. Those are some pretty outrageous shipping charges.

bull51

Asphalt,

Prior to covering you P-51 did you perforate the sheeting to allow the gases to escape and prevent bubbles?

asphalt252

My Feedback: (5)

bull,
No I never do that with ultracoat you just don't need to especially on that wing the sheeting there is way to thin already and doing that will make it weaker. I did however put some Balsarite stuff on the bare wood around the nose about 12� back. I did this to help the covering stick better when it gets oily and older. Due to the thin wing sheeting I glassed it with 3/4oz. cloth to make it stronger to handle (can’t poke a finger through it now).How I glass my planes. Make sure your plane is finished sanded smooth, then spray it down a little at a time with spray glue 3-M is best just work in small sections. Then apply the glass cloth over that section and move to the next section you can overlap about a ½� or so. Don’t rub on it much at this point trying not to disturb the weave just get it all covered with the cloth. Now get some Z-Poxy finishing Resin you mix this product 50/50 then take that amount and mix it 50/50 with denatured alcohol. You’ll end up with a mix about the consistency of skim milk. Now with a cheap 2� brush simply brush it on all over the glass you’ll have plenty of time to work with this mix so don’t worry about that. Just get the glass and underlying wood good and covered with the stuff. When it sets-up the glass will fuse to the wood making a super light but strong laminate structure similar to modern full scale fighter jets. Now sand it all smooth again but don’t go through the glass then I fill the weave with lightweight wall spackle. Apply the spackle with a damp sponge to the entire glassed surface don’t worry about being neat, then sand most of it off with a fine paper silky smooth and apply your covering or paint. If you do this to your wing like I did and that one day you need to put her in on her belly on the grass because her retracts failed. You can relax, go ahead slide her in on that wing, for you know she will survive to fly again another day.
Tip! Belly landing the P-51 is not for the faint of heart you must drag her in on the tail first. Let her touch the ground aft of the radiator scoop this will slow her down nicely for a smooth slide across the grass. If you try to land on the CG as you do when the wheels are down the slope of the radiator scoop will launch her back into the air 10' or more so fast you will not be able to recover from it. She will then stall and nose in destroying your plane. I’ve seen this happen so many times it’s best to find some tall grass to land in this also helps.

bull51

Asphalt,


Just when I thought I could get away without glassing it. I've never glassed before and read several posts about it. All stating basically the same methods you do, but somehow you make it seem simple. Is it really that easy, or will I get in over my head. I have had some experience with spackle and have learned to call the proffessionals when it is time for spackle.

I sheeted the top of the wing and all is well. the twist is out, or never existed, I'm not sure which.

I fly on a hay field with a 30yd X 80yd runway cut in the middle. Until the farmer hays it, there certainly is no shortage of tall, and I'm talking lose your plane tall, grass around. I have made several crash landings in the hay with my NexStar select with no damage. Love that hay!

jamie_duff

Thooper!

Even the retractable tailwheel is causing modifications. The retract horn on the tailwheel routes right through the kit's intended Elevator pushrod.

Beginning to wish I'd built this thing straight out of the box.

I've got some of the fuselage formers in, but it's not looking too pretty right now so I've held back on taking photos until I get things tidied up to a more presentable standard.

PaStang

just curious, when you glass the wing , does it make up for the step between the leading edge and the sheeting ? or is it best to sand smooth and glass over the leading edge also ? will a straight edge and some clamps hold down the sheeting on the ribs at the leading edge? thanks in advance . PaStang

jamie_duff

Sand it smooth, get it as near perfect as you can get. The glass is only really there to toughen the wood up and give a hard finish to work on with fillers and paint etc.

Asphalt252 - did you need to cut F11 to clear the tailwheel? Mine fouls up by a long shot. On the plus side, my Robart 3/8" x 1/2" cylinder is in and rigged, and the tail wheel works

bull51

PaStang,

I wish I had an answer before I sheeted my wing. I tried to use clamps, but they slid off due to the countour of the ribs. I ended up using T-pins to hold dowm the LE sheeting and magazines to do the rest.

asphalt252

My Feedback: (5)

Bull,
Yes it is very easy to do so simple and the spackle is put on with a damp sponge very thin you will not even be able to see it on there. All this does is fill the holes in the weave of the cloth, then sand to smooth finnish. I did 1/4 of the wing at a time top-left then top-right then bottom-left and bottom-right. After you get it all covered with the glass find some clean plastic empty butter containers to set the wing on as you apply the Z-poxy. The Z-poxy will not stick to these and you can do both side at the same time.

PaStang,
Pin that baby down to the LE, sometimes if you have some tuogh sheeting you can soften it up by getting it wet with ammonia. Bend the sheeting around something round till it dries then glue it to your wing. You will not need to fight it when it is already curved to fit just right.


Jamie,
No sir mine is mounted to F-10 in the same scale location the kit one was to be mounted in. When up my wheel is about 1/4" away from F-11 and it works so smooth and sweet see pic.

bull51

Hey,


No fair, my "double tapered" balsa aileron and elevator stock are not double tapered at all. The LE's are flat! More sanding to do, LOL.

asphalt,

Did you use the Robart 121 tail wheel retract? Did you have to shrengthen the mount or move the rudder push rod as jamie suggests?

P.S. I'm working on finding an unused ID for yahoo messenger, it's not easy.