Fragmentum

My Feedback: (8)

I think if I am going to go the FlightMetal route, I am not so sure that a 'glass smooth' surface is all that necessary, although I don't think any of the glass weave should show through the FlighMetal finish....
The epoxy 'flow coat' may be heavier than the sanded down primer overall, and that would not be good. I think on a larger plane, like 1/4 scale or bigger where the wing loading would be less, then that would be more acceptable.
I will try to find someone to concur with on this.

I am working on the engineering to install the drop tank pylons and positioning of them and the tanks.... Not sure if I will make them droppable at this stage as there are already an ungodly enough wires for all the other servos as it is...!!!!

Fragmentum

My Feedback: (8)

Just some preliminary alignment and seeing how the pylons will fit under the camber of the wing, This is a Firepower tank/bomb drop set and the engineering of the kit is very well thought out and executed. Should be plenty of material to support the finished pylons once cut and sanded to fit. The pylons may not end up in the exact scale position, but will be close enough for the look and functionality of this setup.

dufault

I was unsure whether I needed a glass smooth finish as well. It just turned out that by the time the weave was mostly filled it was super smooth after the 400 grit sandpaper. One thing that you might notice with your sample is that any spec of dust that is on the surface shows through. My gear cover doors are only sanded down from the glassing, I might try to cover them in the flightmetal and see if they look alright. The curves are turning out to be somewhat tricky, Im sure the cowling is going to take some time. The wing looks amazing so far.

dufault

Slowly making progress on the wing. So far so good with the flitemetal. I have not put in any rivet details or done anything to the actual flitemetal itself. Covering the radiator scoop was interesting but came together pretty good.

Fragmentum

My Feedback: (8)

I got a lot done on the drop tank pylons, and they are just about ready to attach to the wing. I have to complete the fiberglassing of the wing and complete the construction of the 75 gallon drop tanks. The tanks and pylons will probably be painted and detailed further, and attached after the airframe is completely detailed.

BradSD

My Feedback: (9)

Looking good! Im still checking on ya from time to time. Works of art here, really nice work!

prgonzalez

A GP P51 kit is my next to go onto the building board this month. So, I have been watching this thread for a while.

Fragmentum,

Definetely you are building a very, very, nice detailed model. But, I wonder how much weight you are adding to this small P-51. Have you check how much you have added already?

Pedro

Fragmentum

My Feedback: (8)

I did weigh this plane some time ago and there is a post to this thread not too far back. So at that time I believe I was in the 6 pound area. Still not bad wing loading for this warbird.

Fragmentum

My Feedback: (8)

Finally got the wing fibergalssed along with the flaps and ailerons. I’ve decided to ‘flow coat’ the entire fuse and wing for a smoother cloth weave fill prior to primer.

I also ordered up a scale exhaust from Tony over at Pacific Scale Aircraft www.pacific-scaled-aircraft.com. It is a little oversize for this scale, and if it is very noticeable, I will rescale it as best I can for what I need.

Fragmentum

My Feedback: (8)

Dave Platt was right when he says in his Scale Modeling’s Black Art Series ‘Building and Fiberglassing Techniques’ Volume 3 that sanding the plane after the flow coat process is completely dry is the WORST part of the whole building process!!
He says the biggest mistake in prepping this surface for primer paint is to start out with too fine a sandpaper, and that the initial sanding should be done with 60 weight, which I used, and then follow up with a 220 or 320 grit. Surface will be ready for primer then. I have yet to do the fuse, but finished up the wing and all the control surfaces. I did get through the epoxy and fiberglass cloth on only one spot on one wing tip. Surface is very smooth and ready to finish the wing fillet then priming.

The surface looked pretty shiny after the flow coat application.

Fragmentum

My Feedback: (8)

Except for the final fine grain sandpaper work on the wing and fuse, it is ready to paint…. After the wing fillets are completed. This step now finishes the project of hiding the wing-to-fuse joint.
After generous coats of parting solution is sprayed on the inside and outside of the fuse fillet completed earlier and drying, the wing is mated to the fuse. Polyester resin with micro balloons is mixed and layed down on the wing and up against the fuse fillet so that the height is just a bit higher than the 1/16 to 1/32 inch lip of the fuse fillet.
After this dries, I will sand it down to the height of the fuse fillet and smoothly finish the flair on the wing.
Only one side at a time is done so that the wing can be ‘cracked’ loose from the fuse when it comes time to part the two….
Wish me luck on this as this is the first one I have ever done!!!!!

I got a little of the water soluble parting solution from a local automotive and truck refinisher that uses the stuff in gel coating covering application. Dave Platt uses a material called Partall mold release agent (available from fiberglass supply places and some boat shops) and this stuff I got is made in Seattle, where Partall comes from but came out of a different brand bottle. It appears to be the same green color and consistency. I do not have a spray gun or air brush (YET!!!) so I picked up a Preval Spray Gun at NAPA that worked just fine.

I’ll know tonight if this process worked like it is supposed to…!!!!!

Fragmentum

My Feedback: (8)

The wing fillets are DONE!!!

First, I did not flow coat the fiberglass area along the fillets made on the fuselage. I did this on purpose so that final final sanding could be done after the fillets on the wing were finished.

I applied the polyester resin with micro balloons on the wing up to the fuselage fillets and a thin layer over the wing fillets. After curing overnight, I used 80 grit to carefully sand and blend the wing fillets on the wing surface then on the wing to fuse joint only to the point that after rubbing this joint with my fingers to get the dust away, just discern the difference in the color between the wing fillet and the fuse fillet (the fuse fillet was darker brown). I then smoothed the whole area with some 320 grit. Since the fuse fillet was not flow coated, I sanded down to where I could see the weave in the cloth.
I inverted the structure, unscrewed the wing bolts and then gave the wing a sharp rap to dislodge it from the fuse. After removing the wing I lightly cleaned up the joint with some 320 grit on a block to keep the joint square. I had sanded down enough that the separation was nice and sharp.
While the wing was mated to the fuse, I drilled down through the wing and fuse in the bolt down area and inserted a guide pin. This helps keep the wing aligned perfectly every time. There is too much slop in the wing mount bolt holes to do this, and your paint job and the alignment integrity of the wing fuse to keep from sloughing off the fillets will thank you later….

I completed the fillet work on the opposite wing and made sure both fillets were smooth. I then fiberglassed both wing fillets to make them stronger. After carefully trimming the fiberglass along the fillet seam on the wing and sanding smooth the area where the wing fillet fiberglass meets the wing, I then flow coated that area AS WELL AS THE FUSE FILLETS…..
After these had dried I then reassembled the wing and fuse and sanded the wing and fuse fillets together to final blend them with 80 grit and then 320 grit sandpaper.
The fillets look great and will blend the wing and fuse together nicely after painting and/or FlightMetal treatment.

Fragmentum

My Feedback: (8)

The final sanding before primer is DONE!!!!

I might be a little premature on this next step, but I was just putting off all that final 320 grit sanding of the surface before the primer.

I cut all the trim tabs out of the rudder, elevators and ailerons, then glued them back into place to give them that 3 dimensional look. I am hoping that the visual will look OK after the primer coats laid down and sanded off. I will complete the trim tab actuator detail in the final paint process….

Oh, yea, I am in the market for a couple airbrushes and could use some ‘seasoned’ recommendations. I am planning on using WarbirdColors for the dress up on this plane and HVLP process.

I am leaning heavily towards an Iwata Eclipse HP-CS and a Porter-Cable PSH2 for the airbrush use….

BUT FIRST…. Primer and more sanding….!!!!!

dufault

Paints on, control surfaces attached. All that is left is to install a few servos. Paint turned out pretty good for my first try at it. The rondels are a little blurry but it works.

mschulz531

Fragmentum, haven't heard from you in awhile...how are things going with your build?
dufalt, your paint job is excellent, nice work!

I've been looking at what I've got and what I need to start building my P51. I have a question about the engine...the plans call for an OS .70 4 stroke and I have a Magnum .91 4 stroke engine. When I laid the engine on the plan, it fit over the OS .70 almost perfectly, so I'm fairly confident it will fit.
Regarding the weight of the engines...the O.S. 70 weighs in at approx 22 ozs and the Magnum .91 fs weighs in at approx 22 ozs!
So to me this is a no-brainer (since I already have the Magnum .91 fs)...am I missing anything here?

Peace,
Mike

rglgatortail

My Feedback: (7)

I too was going to build mine with an os 70 but when i got to the part of preliminary balance i figured out that i was going to use almost 7 ounces of lead in the tail so i can imagine that you will be doing the same thing so you might wanna think about moving your firewall back about maybe half an inch or maybe more if you are going to use the magnum 90. I ended up using a thunder tiger 46 pro then ended up with a os 51 ring engine breathing thru a pits muffler and i only used two and a half ounces of lead in the tail.

mschulz531

rglgatortail,
Thanks for the info about balancing...I don't like the idea of adding that much weight to the tail to make it balance....what if I move the rudder and elevator servos towards the tail...do you think that would be enough to offset the heavier engine?
Perhaps I could mount the servos on the tail section like some sport planes, but that would really kill the scale look of the plane, although with the rudder tail wheel and non-retract landing gear, I'm not going for exact scale looks anyway.
This is my first P51 so I'm not trying to get too elegant with it...you know...keep it simple.
Your comments are causing me to reconsider using a 4 stroke, but I really like the sound of the 4 stroke, so I think I'll keep moving forward with this plan.
Thanks again for your comments.
-Mike

Fragmentum

My Feedback: (8)

Mike,
My building efforts are on hold for awhile. I have to build a paint booth, and although I have the plan and the bill-of-materials as well as my new spray equipment, summer is almost here and with a new Harley in the garage, my discretionary (?) income has shifted towards getting it ready for the summer riding season (lowering kit, new seat and other 'refinements').

With regards to your engine choices and weight & balance, a 4-stroke engine was MY choice and I am going with a Saito FA-82a. Your biggest 'weight' item that you can move fore and aft will be your battery, and I suggest you opt for a 5 cell 6 volt pack. You will have better power redundancy, a little more weight you can shift to set you weight & balance point, and better servo response during flight.

Also consider a smaller fuel tank. Consider what your actual flight time per flight would actually be, run your engine on a test bench setup at 3/4 throttle for that length of time and add 20% more fuel and that would be a good size tank to install. This will reduce your nose weight as well.

I think your choice of a Magnum .91 is a bit much for this airframe.

Good luck!!!

Fragmentum

rglgatortail

My Feedback: (7)

yeah you can consider using a bigger battery and then finding a home for it in the back part of the airframe then using a volt reg to keep the numbers at or under six volts, and or consider using a smaller tank but the last time i remember that you balance the plane with no fuel ready to fly at the cg point so the smaller tank would only consider to people that have to worry about strict cg and that would apply to pattern guys that has make a flight without the plane changing attitude with less fuel as the flight progresses so that dont come into play for this plane, and or consider to putting the servos in the tail you wont really make up the weight delima considering that the servos in all total maybe three ounces total and that is counting all the hardware from mounting the servos to the control surfaces so you will still have to think about up to four more ounces to lead in the tail so one still has to think about what to move and or what to install in what part of the plane to balance out either a magnum or an os four stroke. as much as i wanted to hear the sound of a four stroke in the mustang you will have to consider in making changes to the plane to hang that heavy motor in the front of it that is why i suggested in moving the firewall back pretty much half an inch or more but i dont have my notes and i dont remember what notes i made on my plans. i think that saito makes the lightest four stroke you can find so if you really want to hang a four stroker maybe consider to getting a 70 saito because it will have more power than that magnum 90 and you wont have to swing a prop that you need for that magnum as compared to the saito 70. i was at the building stage of the plane when i had the os 70 hanging there and i got the spinner and the wooden spinner ring mounted to start measuring and sanding to install the wood cowl cheeks and then i said hold on let me check this balance and i said no way when i kept adding weight to the tail i did check with a 2400 mah sub c pack four cell sitting on the tail feathers and i still could not think about what changes to make to get it all to work so my os 70 came off and the thunder tiger took its place to make it work. so this is some stuff to think about i also have pics in my gallery if you wanna check them out.

Robert

mschulz531

I've got a question about the dihedral in the wings...I've just completed building the wing halves and when I put them together to check the dihedral,
I've got almost 2inches under each wing tip instead of the 1-5/8 inches as specified in the building specs.
My bad, I must have have screwed up the angle of one or the other of the W1 ribs when I glued them in. (:<)

Any ideas on how to fix or comments on whether the increased dihedral will cause flight problems if not fixed?

If I have to I can build a narrow balsa shim to put between the wing halves before I epoxy them together that will reduce the dihedral.
Measure twice...glue once....maybe for me should be measure thrice...then again...then glue.
I used a wing jig to build the wings, but it did make measuring the dihedral of W1 more difficult.
Still not decided on the engine..but I've got time to decide...this is my "bad weather" building project, so no rush.

-Mike

Fragmentum

My Feedback: (8)

This is what I found out on my build as well. I fixed it by making a tapered rib to fit between the wings then epoxyed it together after jigging the wing halves on the bench at the proper dihedral. I then added the kevlar plate to the spars for strength as I did not want that thick layed of fiberglass cloth on the bottom of the built up wing.

andernamen

My Feedback: (3)

Anyone have a spare fuze for sale? I crashed mine recently. Wing is good, but I need a fuze. If someone has the plans and/or parts or a partly built kit, I'd consider that as well. PM if you have anything.

heritageman

My Feedback: (4)

Fragmentum, have not heard from you in a while. Would like to see where you're at on the build.

basketcase118

where can I get these Beckman concealed actuators. I am in need of 4 of them. I checked the web site tou gave but I still cant find them. please help

Fragmentum

My Feedback: (8)

Since my last post of 6/5/2010, there has been no further progress on my build. I am hoping when the weather warms up here sufficiently, I will move ahead and get my paint booth built and get my plane at least primed so I can get to surface detailing. Our economy has forced me to go to part time employment during the winter months, and hampers discretionary income for this and other projects.