FT Flyer+2+

First, let me say that the FT Flyer is inherently a great build.  As is, it flies nicely.  But as a new flyer, and one just transitioning from a plane with all sorts of electronic aids (SAFE) I am still pretty much crash-prone.  I found the assisted flying to be a great confidence booster because you get airborne in a hurry.  That is great.  But the downside is that it did nothing to teach me about over-control and the resultant ground-thumps that I encountered when first “flying a model all alone”.  I totally destroyed this Flyer over the period of a month or so.

I decided to try to make a few changes in the process of rebuilding.  I noted where most of the damage occurred and tried to address those areas in the modified rebuild.  I call it my Flyer+2+.  Some ideas, like adding a KF step, came from comments on the FliteTest forum.  I don’t know how it changes the flying characteristics, but it sure makes the wing survive crashes much better.

The wing-build began with a “stock” FT Flyer plan.  I added some paper to the leading edge so I could lay out the step portion.  I folded the paper over the original plan and, using a SWAG of 4” for the chord at the centerline and 2 1/2” at the wing tip, I drew my proposed KF Step.  By trimming that to match the original wing pattern I had my new leading-edge pattern.  In addition to the KF Step, I did a similar addition to the plan, adding area to the wing.  I increased the chord uniformly by 2” using the same angle for the trailing edge as on the original plans.  That is the “+2” (Mk. I version).

I built the plane with a more traditional “fuselage” which strengthens the wing joint and the tail assembly.  That brought the tail to the same plane as the wing, which it abuts, adding even more strength.  The fuselage is a simple cut, score, fold, glue construction.  I actually used an FT Power Pod plan to determine the cross section and tabbing, just increasing the length to fit my wing and tail assembly.  The fuselage is glued to the wing, strengthening it laterally and decreasing the tendency for it to get “flappy” after a few crashes that loosen the center joint.  This picture is of the Mk. II version.  (More later)

I had to come up with an entirely different “power pod” since I still wanted to be able to get easy access to the electronics and replace as little as possible after ground thumps.  Notice that it actually has several sections, so it is a bit trickier to build, but I am pleased with the added strength it provides.  The dimensions for the electronics platform are built to the same cross-section used for the tail boom on the original plans.  The outer section is a cut-to-fit section, but by the time you get the idea for how the FT cuts and joints are made, it is quite easy.  Basically, the finished inner flat is 2 1/8”, the finished sides 1 1/4" inches.  (These photos are of my Mk. I version.  More later.)

With the motor I am using, even with fairly heavy landing gear, in the configuration of the MK. I version I had to mount my battery way forward.  It actually had to overlap the back of the landing gear wire.  I decided to shift the CG a bit by extending the nose 2”.  That is the “2+” part of the name.  The new pod is 6” long.  The added length also gives me more room between the thump and the wing.  Changing the wing did not appreciably change the CL.  The battery can be mounted an inch or so further aft than previously.  I have been using 3S 1500 mAh and 1300 mAh batteries.  The plane carries them with no problem.

Here is the Mk. II pod in place with several other minor additons discussed later.  Note that the Mk. II pod is actually easier to build.  In the Mk. I version temporary spacers had to be used to keep the two sections the proper distance apart so they would slide into/outside-of the fuselage section.  In the Mk. II version, by using three pieces of foam 2" long and of the proper width, butted against the firewall, you can glue the whole assembly together.  That not only strenghtens the forward end of the pod but "builds in" the proper spacing between the two sections.  You may notice that as a "belt and suspenders" type of guy (retired engineer) I also beefed up the firewall with some foam glued behind it inside the inner, elecronics section. Like Tim Taylor, I always go for "More Power!" so the small added weight didn't bother me at all.  (I never built a bridge, but I guarantee that any I had built would never have fallen down.)

To make the unit more durable I used plastic for the firewall.  Generally the earlier flying sessions would have a crash or two and end with a broken firewall.  I happened to have some of the plastic cut from storage containers like Rubbermaid or Sterilite.  It is very tough.  Now, the damage is moved back to the foam pod, but for me those are easier to make and repair than firewalls.  Obviously, the firewall is built a bit wider than the original plan to accommodate the wider pod.  It is about 2 3/8” wide but, instead of cutting it to that dimension, it is just as easy to lay it out using the front of the new pod as a guide.  Use the "stock" FT firewall height.  The plastic cuts very well with a fine blade in a Sabre Saw or, with a lot of patience and some effort, with a hobby or drywall knife.

I fitted a double-thick piece of foam board between the top of the firewall and the wing.  That transfers some of the energy of crashes back to the wing/fuselage area and the pod has held up quite well.  I just fitted that part in place with packing tape.  I will mention heat shortly.  If one leaves out this part, it would be another solution to the cooling problem I encountered.

A few minor details might also be of interest.

I did notice that in the stock power pods my ESC was getting hot enough that the adhesive on self-stick Velcro@ was softening and the ESC actually moved during crashes.  I added an air scoop to push more air over the electronics, which shows as the white foam in the picture of the now-deceased first plane.  For this plane I put a large scoop, made from part of a plastic bottle, right up front.  It is not very elegant, but it is extremely functional.

The wheels are lids from gallon juice jugs.  I cut press-fit circles from blue foam insulation board using a hole-saw.  The two caps are glued together with the foam and hot glue holding them very well.  Like I said, the gear is heavier than if I had used pure foam or commercial wheels but it works great.  The plane will taxi quite well on the short grass at our local flying field.  Landing on pavement does not tear up the wheels.

All these changes, combined, added weight of course.  All-up, with a 3S 1300mAh 25C battery, it comes in at 17.6 ounces.  I am using one of Grayson’s “disposable foamie combos”, the 3D version, so power is no problem.  That was so even on the original version of the FT Flyer.  With a 3S battery and a 9x4.5 prop, half-throttle gives lots of level-flight performance.  Full-throttle climbs are still overwhelming to me, generally resulting in the plane being upside-down, then in a vertical dive followed by a thump.  Even if I start the climb 3 mistakes high.  But that is just me, and I am getting better with the help of my FT Flyer+2+.