Value Hobby Chinese ARF 80.5 inch P 51 Build
 

I've seen several "build" threads on really nice warbirds from Top Flight and Great Planes... Would it be OK for me, a veritbal novice, to record here a timeline, with plenty of pics, of a new P51 ARF build through maiden flight? I hope to achieve the kind of detail included with a P47 build thread that inspired to get a really big ARF and record what works and doesn't...

This will be an active thread... I hope (quite desperately) that you'll participate. I've had phenomenal results here on RCUniverse in regards to rebuilds, motor recommendations, and other kinds of help that have made this hobby extremely valuable and rewarding for me.

So... I humbly request a go ahead from you, the Warbirds forum gurus, permission to do just that...

thanks

Frank Migliaccio

RE: Value Hobby Chinese ARF 80.5 inch P 51 Build
 

you dont need our permission and as long as it is a warbird i aint coplaining;), bring it on

RE: Value Hobby Chinese ARF 80.5 inch P 51 Build
 

nor do you need the approval of a moderator

gopherit

RE: Value Hobby Chinese ARF 80.5 inch P 51 Build
 

Yes go for it! All ideas welcome

RE: Value Hobby Chinese ARF 80.5 inch P 51 Build
 

Thank you, Ram-bro... I'm going to blame you (lol) when someone gets upset at me for posting too much...

This is a chinese made 80.5 inch ws P 51 ARF... I bid/bought this ARF on ebay for $196 plus $79 shipping. I did find the exact model and possibly the US distributor at Value Hobby. [link=http://www.valuehobby.com/airplanes/almost-ready-to-fly/30cc-giant-scale-p51.html]30cc P51 ARF[/link] I recieved two boxes today...

I opened the boxes and found a few defects... which you will see in the pics below...

The ebay seller says this ARF is based heavily on the World Models P51 and directed me to that website for the instructions to complete the kit.

List of defects so far:
There was a perforation of the top of the right wing by the underwing tank mounts on the left wing.
The horizontal stabs have mounting eyelets that were broken
The main wing tube was missing
The drop tanks have broken fins
There are cracks/breaks in the ply fuselage box

I'm very worried that I may have gotten a rotten deal... The seller explains in a reply that I should expect some defects due to shipping... (I don't know about that)

RE: Value Hobby Chinese ARF 80.5 inch P 51 Build
 

The seller is full of bs. Id tell him make it right or have ebay take care of it. Hope to see this one finished

RE: Value Hobby Chinese ARF 80.5 inch P 51 Build
 

So here is your problems and poss solutions below.

- There was a perforation of the top of the right wing by the underwing tank mounts on the left wing.
Mine get hanger rash all the time. . CA any broken wood, add a film or aluminum heating duct tape patch and paint to match or make it a access panel.
- The horizontal stabs have mounting eyelets that were broken.
Not sure from pics, but reinforce broken tabs with plywood and then use hard balsa triangle stock on the underside to add more strength to fuse/stab joint. This is you biggest fix as a strong stab is kinda critical.
- The main wing tube was missing
Buy a broom stick or wood dowl to fit. Cut and epoxy wings together.
If it is to be a two piece wing. Aluminum tube from Chief aircraft like a big acrobatic plane. 1.5 inch or so.
- The drop tanks have broken fins
Looks like bombs. Make 4 fins from 3/32 ply. Glue to body and paint.
- There are cracks/breaks in the ply fuselage box
I would use a ply doubler on wing bolt area and anything needed for the engine mount. Another option is carbon fiber Matt. CA to inside of plywood. More expensive but almost no weight over ply option. Could also do fiberglass cloth instead of CF.

RE: Value Hobby Chinese ARF 80.5 inch P 51 Build
 

FireBee...

thank you for the shot in the arm and for loaning me some "balls"... I agree... They are all fixable.. I mean, part of the hobby is figuring stuff out... Instead of asking the guy for a refund, maybe he'd send me some dough to buy some stuff to get the model built and in the air.

I'm looking over the components and except what I've listed above everything looks okay...

The wing is gigantic! It isn't completely sheeted... my question is that since this plane has such a huge wing area and a bunch of imperfections in it and on the fuse what do you guys think about pulling the covering off and glassing the whole thing? I mean... I wouldn't have to worry about hangar rash poking a hole or using a iron on covering after putting some 3/4 oz cloth and thin epoxy on the wing, the fuse, and the horizontal stab... I'll make it a one piece wing at that point...

Also.. with glassing the whole thing I kinda eliminate some bad ARF-build glue issues, don't I? Plus, I've got a can of spray paint already... should be really fun...

I'm going to be using a DLE 30 and a 4blade prop.. I don't need speed.. I want it to fly scale... have a bunch of "get out of trouble" thrust...

RE: Value Hobby Chinese ARF 80.5 inch P 51 Build
 

I do not think a 30cc engine will be able to spin a 4 bladed prop. If so, it will have to be a very small prop which will not pull the plane at all.

RE: Value Hobby Chinese ARF 80.5 inch P 51 Build
 

well.. so much for the 4 bladed prop idea.. it's the only motor i have so I'll stick with a Zoar 18X8 then... the kit says it's a 20 or 30cc plane.. should I be thinking go bigger on the motor?

RE: Value Hobby Chinese ARF 80.5 inch P 51 Build
 

I fly my Hanger 9 80 inch P-51 with a 26cc gasser and even though it takes a little more runway to get off the ground (looks cooler that way) it flies nice in the air. Not near as fast as a 150 4 stroke, but looks good and handles well in the air.

RE: Value Hobby Chinese ARF 80.5 inch P 51 Build
 

Wow, that didn't take much to change your mind. Of course, since there really aren't any 4 blades readily available, that'd be a good reason to blow off the idea. However, there are 3 bladers and a fair amount of them. Warbirds often look a bit puny with 2 bladers. It'd be worth considering a 3.

If the kit says 20-30cc, then you should be able to fly the sucker with one of them. What worries you that your 30 won't be enough?

RE: Value Hobby Chinese ARF 80.5 inch P 51 Build
 

I bet the 30 would be alright, but I mostly see 50cc in the 80" heavy metal. The whole prop thing though, I prefer 2 blades. Mainly for performance, and secondly because I break so many! lol

RE: Value Hobby Chinese ARF 80.5 inch P 51 Build
 

You've mentioned the wingspan, but that's not always what decides motor size.

What do they advertise as the expected flying weight? Thats more important when choosing an engine.

RE: Value Hobby Chinese ARF 80.5 inch P 51 Build
 

As far as 4 blade prop on a DLE 30, it woulb be something like a 15/16 x8. And I am sure you will not like the proformance. I ran a DLE 55 with a 22x8 xoar on a TF 1/5 (84in ws) and it really torn up the sky.
Switched to a Beila 4 blade 19x8. Still flys great, but 10 mph slow and you need to use alot more rudder in the turns.

Chris923

RE: Value Hobby Chinese ARF 80.5 inch P 51 Build
 

What brand would you recommend?

RE: Value Hobby Chinese ARF 80.5 inch P 51 Build
 

I don't know of any one having a 15/16x8 4 blade. You could have zinger make you one. Zinger props are not the most efficent, but 4 blades are not efficent either. IMHO you fly 4 blade for the "look" not proformance.

Chris923

RE: Value Hobby Chinese ARF 80.5 inch P 51 Build
 

I highly recomend you stick with/plan on using a 2 blade prop. 2 stroke engines, especialy the small to mid-size gassers, don't do well with 3 and 4 blade props. Besides, your Mustang would look really funky with a dinky little 3 blade prop in front.

Old Dawg

RE: Value Hobby Chinese ARF 80.5 inch P 51 Build
 

I agree with the Old Dawg!

Chris923

RE: Value Hobby Chinese ARF 80.5 inch P 51 Build
 

Guess nobody told my Corsair. or my Thunderbolt or the Spitfire or the Hellcat about that efficiency myth. OK, it's not a myth. It's correct in theory, but in practice, a couple of the planes pictured have clocked over 110mph on radar. And my 60 powered Yak54 didn't get the memo either. It's sold as a 60-90, yet has unlimited vertical with that 3 blade up front. There are a couple of 2s that will match it, but the 3 is quieter and flies better on hot days.

What isn't a myth about model props is there is almost absolutely no 3 blades available. Forget about no range of choices, we don't have but a very few you can find at all. What does work out in practice is that it's worth the effort to actually try what you can find to see how much or how little the loss of efficiency matters. Having flown a lot of 60-90 powered warbirds for 6 years now with 3 bladers, it's very clear the idea we should shun 3 bladers is BS.

With model motors, what matters most is the matchup, not the theory. We don't have variable pitch, constant speed, or much else full scale has to tune the power. What we have are fixed pitch, mess produced things that vary all over the map and really offer gross differences in pitch and base efficiency between makes. You'd be amazed how many times you'd find a much better prop for your specific model/engine if you could buy them in half-inch diameters too AND you did serious prop testing. If you look closely at the Spitfire's prop, you might notice that engine on that airframe gave better performance with that prop diameter trimmed. (Of course, you can do the same with 2 bladers btw.) My point is that the props we have to choose from make choosing props more of a lottery than a science. IMAC guys have very good availability now. And thanks to that have discovered just how lame the efficiency theory is applied blindly to our models. The real shame is that we really don't have but a couple of choices for our 60-90 size warbirds.

RE: Value Hobby Chinese ARF 80.5 inch P 51 Build
 

So, I went to town last night on this project... I've started by pulling all the covering off and finding an amazing array of broken or simply unglued "stuff"... in some of the pics below you'll see actual seperation of glued surfaces...

I'm going to reglue all wood intersections with T88. I'm going to glass the whole exterior of the plane with .7oz cloth and WestSystems glass. I bought a EME55 gasser. I have Hitec 5645 X 6. I'll going to be using a 10channel 92104 (Airtronics). A red RCSSJK power expander with two (2) 2100MAh Life for reciever and servos. I'll be using a 2100MAh Life for ignition as well.

I've started sanding the wings leading edge to round it off... it was almost square under the covering...

RE: Value Hobby Chinese ARF 80.5 inch P 51 Build
 

BTW... I know many of you are wondering why I'm going to use a 55cc motor on a 30cc plane... The DLE30 weighs 2.4lbs.. the EME55 is one pound heavier at 3.4lbs. I thought that since I'll be adding a lot of weight with fiberglass, etc that I'd need extra HP to go really fast... I'd dig it if I can get this plane to 130MPH. (i actually wrote 150 but that sounded ridiculous).

The EME55 comes with an electric starter, too...

http://www.taildraggerrc.com/eme-gas...cessories.html

RE: Value Hobby Chinese ARF 80.5 inch P 51 Build
 

I just put one of the electric start EME55s in my ESM Fw-190A. It's really cool! The starter adds 19ozs of weight to the engine, so it's actually a 4lb 6oz engine. It's a wash for me though, since the plane needed 1.5 lbs to balance when I had a DLE 30 in it. :) Hoping to get it fired up next week, but likely won't be able to fly for a few months because of weather. [:@]

My plane is technically a 30cc bird too, but at 17.5 lbs on a 70" wing, the extra power will only help. With your wingspan being closer to 80", I would say that a 50cc engine will be just right once you glass the airframe and add your flight pack.

Good luck on your build. Looking great so far!

RE: Value Hobby Chinese ARF 80.5 inch P 51 Build
 

I started with the wings first... I've gone through and used T88 (structural epoxy adhesive) on all the wood intersections I could reach... I used 1/3 inch triangle stick everywhere i had new sheeting going. there were only 2 stringers in the wing and one of them had now glue (lol). I used 3/32 bassword and cut cross-grain pieces. I've gone ahead and used 3/32 balsa sheeting to close up the wing. I wick'd the pieces in with thin CA (MXBon 105) but final glue was 5 minute epoxy (Kwik Bond).

T88 needs to set overnight so it's going to slow much of my progress... I've also loaded up the first 3 ribs at the leading edge (especially around the landing gear mount) with T88 mixed with sawdust (as a filler). I did use Patch n Paint LIghtweight spackling as a filler on the first wing but I don't like the effect... I'm going to switch to WestSystems 105 with 410 Microlight Fairing Filler. (i want the suface under the glass to be as smooth as possible).

I've picked a color scheme... I know its early but I like it... the majority of the surface with be a shiny metalic finish with bright white and royal blue accents and control surfaces (high gloss).

RE: Value Hobby Chinese ARF 80.5 inch P 51 Build
 

I am heart broken.. ready to slit my wrists... light the remaining balsa ablaze...

my brand new, in the box, 5.5HP, EME55cc gasser is too big for the cowling... I knew I was going to cut a bit for the exhaust can but it's also 1 1/2 inches too long and the starter would force me to cut up the top of cowl too (since the motor goes in inverted). The measurements I used (from the web) did not include the spacers/mounts or the starter assembly and electric motor...

damn... i was in such a good mood today, too.

gotta figure something out.