A couple of building questions...

[Marshdweller]

I'm currently building the 900 series Mustang, and have reached the tissue-covering stage. Looking at the way the model goes together has made me think, and raised a couple of questions. If I

• tissue cover the top and sides of the fuselage and the top of the wings
• then attach to the fuselage (so I can put some sort of clamp on the wing/fuselage joint, holding the wing rib to the fuselage side)
• then cover the underside of the wing and fuselage
• then shrink it all at once

can anybody see any problems arising?

I'm determined to get this one flying (after my first attempt's flying characteristics resembled those of a damp feather), so don't want to do anything that will warp the pieces. The instruction manual I got with the first model tells you to shrink the tissue and dope it before finally assembling the model, but I think that assembling it before shrinking will make the assembly much easier. I also can't see how I'm more likely to warp things after assembly than before (since I'm spraying the same pieces with the same water etc.), but I'm well aware that as a beginner I may be missing something important.

Second question is much simpler: How do I cut out the spinner and prepare it for the propeller without making it lose its shape? On the previous model, as I cut the slots in it to slide the prop in, it went floppy and had an oval cross-section at the base.

[Wildpig]

Covering first, then assembly: allows the wing to be placed on a flat surface to dry.

You could cover the bottom of the wing except for the inner bay. (From the root rib to the first rib outward).
Then assemble. Cover the inner bay after clamps are removed.

Those spinners can be problematic. I haven't really mastered the art of spinner assembly.
But, the oval shape is probably a result of not having your cut-outs large enough and is being deformed by the prop. Hard to say without actually seeing the part.

[Mitch]

I have not built the 900 series 'stang but I believe on ALL models, you want to cover each componant completley. Fuselage, Wing, Rudder and Stabilizer.

If you have not done it yet cover the tail first, then wing then fuse. I believe that is the order of difficulty. I prefer to cover dry as I use lite paper and it has ZERO strength when wet. Clamp or pin down the tail and wing as they dry so they do not warp. Then apply one coat of dope. Then assemply the parts, I use large clamps or rig some sort of jig to hold stuff together. Then one or more coats of dope over the entire model and add you decals.

I have not put spinners on my flying models, but if I do I will make a post on that.

Good Luck, Mitch


me109 tail... to show you clamped with magnets, or you can use weights or pins to hold its shape.

[Steve Blanchard]

You definitely do not want to assemble before you finish covering. It is much easier to handle the individual pieces and get a nice neat job before it is assembled. Also, when you shrink each piece makes no difference as to how they shrink. The grain direction of the tissue on the framework as well as whether you shrink with alcohol or straight water etc. will determine the shrinkage. Warping is controlled as Wildpig mentioned by wetting each wing panel, top and bottom together, separately and pinning to a flat surface to dry. After the first panel is dry you then wet the other wing half (top and bottom together) and pin to dry. There is a lot learn and it will all come as you build more models. Oh yeah. DO NOT Shrink the tail surfaces. Get as smooth a job as you can when you cover them and then just seal them when the glue/dope/whatever you use has dried. I hope this helps.

Steve

[Steve Blanchard]

Sorry Mitch. I was writing as you were posting that pic. I do know that many modelers shrink the tails but when it comes down to it, unless you have a really beefy frame, to me the benefits are not there. You could use cap strips as Earl Stahl has on all of his plans (free flight genius and if you don't already know of him, look him up). Another lesson to be learned as you go. Nobody does it the same as anybody else.

Steve

[Steve Blanchard]

I missed the spinner question. I agree with Wildpig. If you cut the slots accurately the spinner should hold it's shape when assembled. It is easier to make your own spinner out of balsa if you own a hand drill. It's easier than you think really. Easier than cutting the plastic to fit the prop. Also if you wreck the spinner that came with the plane and you want to use a plastic one, don't get a new one from Guillow's. Go to the dollar store or even better raid the Easter decorations (if you have them) and use the pointy end of the plastic eggs. There are several different sizes and I'll bet there's one to fit any kit on the market.

Steve

[Mitch]

Thats a VERY GOOD point on NOT wetting the tail. I know the 900 is smaller and my pics are of 400 kit. Moreover 2 or 3 of my 400 series( the count now stands at 8 ) have warpped tails. My pic is of my last construction and that plane came out the best so far. I do not claim to know everything and I feel there are people here with much more knowlede than I. I too learn from reading these other posts... Thank You, Mitch

[Steve Blanchard]

Mitch,

Same here. I've been doing this for a long time and surrounded by many much better modelers than myself and still I get new techniques and work on perfecting the ones I already know. Always learning. that's one of my favorite parts of the hobby.

Steve

[Marshdweller]

Thanks for the advice guys!

My next question:

The wings have a small triangle added to the leading edge which is obviously flat/in line with the bottom of the wing. Should I add a matching triangle gusset above it in line with the camber of the top surface of the wing to (a) add weight in front of the centre of gravity and (b) make covering a little easier?

[Mitch]

The thing I like about balsa models is the potential to easily make changes. Although you may choose to follow the plans exactly and come up with a very nice copy of the original. I choose to leave off details as I intend to fly my models. This past year I built all 400 series plus some more than once. I choose to leave off the gussets and wing fairings. I just make sure I have a good fit. Here is a pic of my 400 series 'stang and focke-wulf. NO wing gussets.

Mitch

[Mitch]

Sometimes I like to give advice and I shoudn't. I have not built this 900 series, and now it sounds like these are gussets inside the wing. I thought they were the gusset for the fairing. I should learn to only give my advice when I know what I am talking about... apologies... I understand that some of these planes have gussettes inside the wing at critical points... I'll be quiet now... Mitch

[Marshdweller]

Sometimes I like to give advice and I shoudn't. I have not built this 900 series, and now it sounds like these are gussets inside the wing. I thought they were the gusset for the fairing. I should learn to only give my advice when I know what I am talking about... apologies... I understand that some of these planes have gussettes inside the wing at critical points... I'll be quiet now... Mitch

Well, there are gussets in the wing near the root, but there are also gussets on the exterior of the wing to give it the Mustang wing shape.

As for your advice, please keep giving it. It may well be the case that you're the one most on the wavelength of either myself or whoever else may be seeking the advice. Either way, a little contradiction sparks debate, and hopefully will draw the wiser and more experienced builders in and then we can all learn not just what to do but why.

[Marshdweller]

I knew "gussets" wasn't the right word! It didn't feel right as I typed it.

[Marshdweller]

Ok, next question:

I've sealed the tail surfaces with my PVA/water substitute for dope and unfortunately, the two surfaces have stuck together in a couple of places. As I'm building this to fly, is this a disaster? Should I really remove all the tissue and start again?

[Wildpig]

The tissue sticking together in the tail will not make any difference as far as flying goes. It's only a matter of appearance.