Originally, I figured making my own spinners would be too much work. So I bought one, paid a premium price, and spent about an hour trying to get it to fit with the GWS props I was using. Then to make matters worse, the spinner was noticeably heavier then the motor I was using. At the very tip of the plane this amount of weight was unsat. Now for a nitro powered plane, this would not be so much of an issue, but I deal with electrics. Then I got the idea that making my own spinner would not be so difficult, I found this website on building model rockets, and figured I give it a try adapted to spinners of course. The result was a custom spinner used on my 109 but what has surprised me the most is the durability of this thing. Originally I made 3 spinners.
The first one was directly glued to the prop, and after more then a few crashes there finally wasnít enough left to glue together as the propeller was cutting away at the bottom. For the second one I changed my mounting method, using a piece of plastic as a backing plate, sandwiching the propeller between the backing plate and prop adaptor and the spinner. The spinner is then glued to the backing plate with the prop fitting nicely in the slot cut. Upon any ďnose heavy landingĒ the spinner pops off resulting in very little damage. Iím still on that second spinner, and Iíve hit a fence or two since then. The best part is all three spinners took less then 45 minutes to make, and they are all light as the foam they are made from, costing nothing.
For this Mustang, I made 4 spinners, each one looking a little bit better then the last. Donít be intimated there is really nothing too it. Well, ok, I did cheat a little bit. Using a drill, preferably press, makes sure the spinner is balanced. Just use some sandpaper to smooth it out, after the wire does most of the work. (Itís best, in terms of shape, to sand as little as possible).
The next step for me was to clean off the table and call it a night, not a lot of work done today, but Iím not on a deadline, and itís gonna storm the rest of the week.
Day 3 time to Glass
Amazingly, Iíve found that a wing will hold together absolutely fine by merely hot gluing end to end in a butt joint. The four parts of the P51 wing were glued with hot glue, two sections butt jointed then cut for the dihedral, then glued to the other 2 sections. Again this is fine for the wings actually flying apart, but is not fine for the overall flex that foam gives under load, especially pulling out of a dive. The simplest and most effective way of dealing with the flex that Iíve found, while protecting the landing surface, is to fiberglass the bottom.
Fiber glassing is an easy concept. But the devil is defiantly in the details on this one. It took me some time to be able to actually get the process so the results look ok, and Iím pretty forgiving. The first attempt showed me that automotive fiberglass resin eats foam, and as a result never really dries. I read Keithís book, bought some foam safe resin gave it a try, still looked really crummy, read some more online topics, looked a bit better. Overall, still sub par. It wasnít until I talked to someone with lots more fiberglass experience then I had that it really rung home. Then I refined my search and found another forum post that had another crucial bit of info. So here is the key:
On the first coat:
Dilute the resin, at least 50% with:
Duh!! Right? Do not use rubbing alcohol from the pharmacy as itís mostly water. Go to a home improvement store, head towards the solvents and pick some up. Donít worry itís pretty cheap, will totally dissolve zap resin and is foam safe. On the P51 my first coat of resin was diluted to about 10% resin, way overkill, but it worked. Mix the alcohol until there is not any resin left on the brush or the bottom of the mixing cup. Iíve found that even the 5 minute stuff will not cure until the alcohol evaporates. 2nd and 3rd coats need much less alcohol, as the glass should be stuck to the surface. Make sure you have proper ventilation and have at it! The fiberglass Iím using here is from a roll I picked up at the Weak Signals show in Toledo last April, I wish I wrote the vendor name down, because it was cheap!
I put on three coats of resin before I called it quits. The used a hobby knife to trim the excess weave from the wing. This is where you are supposta sand with fine grit sandpaper to get a glass smooth finish... Well, thatís not for me Iíve got the support and protection I need, and I can tell just looking at this craft, Iím gonna need all the drag I can get. So let the airflow trip at the leading edge of the wing, especially on the bottom, I donít care. With the wing glassed, Rx, four servos, a 40A speed controller, and 400 Class Brushless, the plane weighs in at 11.7 Oz. Not bad at all. After painting, a canopy, and little foam pilot Iíll bet it will weigh about 13 Oz. Making an AUW of about 21 Oz with 2300 an A123 3S 10.8V Battery. Of course I do have lighter batteries.
Note the aileron control surfaces. They are beyond a doubt, huge. I do not need them this large. At full rate this plane will be hard to control. However, I have noticed that the ability to use flaperons with the Spektrum DX7 is an ability I want. With flaps fully deployed the flying speed will be greatly decreased. For me, this is very necessary, as with the 2300mAh battery I will be getting close to 25 minute flights. At cruising speed even large fields can seem small, especially if they are surrounded by houses and trees, this makes me fatigued very fast. Slowing the plane down for at least part of that flight helps out a ton. The low cost Hextronk servos make installing them at the control surface not a big deal, and there is little to no effect on that surface. I bet there is some excess induced drag, but Iím not going for a speed record.