Build Log Discussion - LA F2 Flyer

[LA F2 Flyer]

My Badland F2 is almost complete. I am closer to the first engine-start. Here is how it looks currently. Next step - build a trailer for it. My criteria are something that can be collapsed to fit in the driveway and that allows me to tow the plane nose forward. Do I custom build the trailer myself, or have someone else do it? Hmm. Thoughts or suggestions?

[Badland-F5 Pilot]

I didn't notice before but those wings came out really great!

[LA F2 Flyer]

Thanks! One wing has a few more wrinkles on the leading edge than the other, but neither is bad. They should fly nicely (I hope)!

[Badland-F5 Pilot]

It doesn't look like it has much dihedral, which I actually like. I've seen some that there's so much dihedral that you know the plane loses some lift, especially out towards the end of the wings. Some is good, smoother stall, easier for the plane to fly level..etc, but then there's too much. Glad the Badland planes don't go over kill on it. As for those wrinkles, just more vortex generators - built in

[LA F2 Flyer]

I have a feeling that the dihedral is a double edges sword, and probably a fine balance. You want enough for positive stability, but not too much that you lose lift, as you mentioned.

Chris had mentioned to me that he had experimented with the dihedral on one of the finished kits he sold. As I recall (and according to my notes), he had said that the ideal spot (so far) was 1.5" of lift for every 48" of span.

I imagine the dihedral remains slightly adjustable by resetting the heim joint at the base of the struts. However, it can't be adjusted too far from the original setting, thanks to the placement of the through-holes for the pins at the spar root, where the wing mounts to the fuselage.

[Badland-F5 Pilot]

So this begs the question of, how do end fences affect the plane with a little or a lot of dihedral? I already know that the fences increase lift by not allowing the air at the tips of the wings to swirl around to the top side causing an increase in loss of lift. How do they affect stall? I would think that because a fence increases lift at the tips, stalls would become more abrupt and require a bit more attention than without the fences? Then take a plane with little dihedral with fences compared to a plane with a lot of dihedral with fences. While the fences on the little dihedral plane would most likely give a very good amount of increase in lift, I would say that it would be similar to the plane with a lot of dihedral. The difference I would think would be in that that plane with a lot of dihedral may be very aggressive on keeping the plane level. To think about the lowering of one wing tip to a more level position, the fence would now increase the lift, while the higher wing would have a loss. That would (guessing here) cause that lower wing to pop back up to equalize with the higher wing. This wouldn't be near as aggressive on a place with a low dihedral. I'm not sure, but that sounds about right to me. I'm most likely missing something though and that would be very possible. I'm just learning about what the wing fences do, how they work, size of them...etc.

[LA F2 Flyer]

"How do they affect stall? I would think that because a fence increases lift at the tips, stalls would become more abrupt and require a bit more attention than without the fences"

Interesting, as I was wondering the same thing. My intuition (which is often incorrect) would think that they decrease the possibility of a stall turning into a spin, because (as you said) they tend to stabilize the plane along the longitudinal axis. However, would they still do so at low (stall) speeds?

[Badland-F5 Pilot]

Interesting, as I was wondering the same thing. My intuition (which is often incorrect) would think that they decrease the possibility of a stall turning into a spin, because (as you said) they tend to stabilize the plane along the longitudinal axis. However, would they still do so at low (stall) speeds?

I think there are two possible ways this could go. Either the fences are going to stabilize the plane in the stall and produce a controlled sink, or if they became out of balance with each other at some point in the stall that the plane flips hard right or left into an almost instant spin? I wish I could put fences on one of the planes in MSFS 2020 and test it out to see what it would do. You'll have your plane ready and flying before I have mine. Let me know how it turns out

[LA F2 Flyer]

I think at that point I fly you out here to test it for me. I'll even rent you a parachute!

[Badland-F5 Pilot]

Uh, no

However at 3K or 4K up, it wouldn't be bad to do some practice and see what reactions are needed to ensure a safe recovery. Being that these are such high drag aircraft I lean more towards the stall/spin not being to radical at all and easily recoverable - and I don't mean with a parachute.

I think I may have to try 1/4" fences and then take them up in 1/4 inch increments to see what performs the best. I'm thinking with the fences and vortex generators, that upper wing is going to have some suction and it's just going to float down during a stall. Trent Palmer did power off stalls in his Freedom Fox and it was just a mushy dissent, stayed upright just fine.

The next question is - with the increased lift, will there be a higher maximum altitude?

[LA F2 Flyer]

Not a bad idea to increase the fences in increments and test. I should be so lucky as to have the plane float down gently in a stall. That would be my ideal for sure!

Now, where do I find me one of those parachutes?

[ksatter26]

Todd left me a msg saying that you dud not route your flaperon cables per the manual and that yours operate more smoothly. Can you post a description? I'm finishing up the mechanicals of my fuselage/controls build and will probably start working the wings soon as the new Polini supplied mount ring does not match the pattern on the 2-piece welded mount Chris delivered.

Thanks,
Kurt

[LA F2 Flyer]

Hi Kurt. I'll try to get some shots of my routing and post them here. The pictures in the build manual are actually of my plane, but I didn't notice any pictures of the lower routing, under the gas tank included.

[LA F2 Flyer]

Adding this to the discussion forum:

The time has finally come for an F2 update. I "stole" a new to me engine from another forum member. (Thanks Allen!)

Thankfully it was a package deal because his adapter was slightly different for the one I had for the Polini Thor 200. As a result hanging the engine went much more smoothly.

After reluctantly drilling some holes in my firewall I managed to mount the radiator as well as all of the electronics.

The battery has been mounted between the rudder pedals and the cables run through the firewall.

I am hoping the expansion tank is high enough. As mentioned, if I bleed the system properly, it likely shouldn't be an issue. I am several steps closer to being able to fire her up!

Let me know your thoughts, concerns, etc.

[Mountain Cat]

The (new) engine has 21 minutes run time on it, plus whatever the factory put on it as break-in. Also included was the registration for Polini. I did not register it so you can in your name for the warranty.

[LA F2 Flyer]

Allen, I am very much enjoying putting it together (although I have to say I don't think I've seen a more convoluted user manual than the one for the tachometer).

You had mentioned that you didn't like the water temp gauge that's in the head. I am guessing you used the one in the upper hose? What didn't you like about the one to the head?

[ksatter26]

My battery is also located against the firewall between the rudder pedals. I simply drilled two 3/16" holes and strapped the little battery in place with a large zip-tie.

I also drilled two holes thru the firewall and inserted rubber grommets as insulators running AN3 bolts thru providing terminal posts for my positive and negative battery leads.

[LA F2 Flyer]

I am still undecided as to whether I intend to run grounds to the airframe. I may keep is a "closed" system with only the engine in play, the way Polini intended it. No need to add more wiring.

But I like the zip-tie battery mount idea. It would have saved me some bending and drilling.

The only reason I had to do so on the last engine is because I grounded my kill switch to the airframe rather than back to the engine.

[ksatter26]

I originally thought that part of my no spark problem was a bad ground. I had created a grounding point by adding a strap to the lower.-starboard engine mount at the firewall.

I have since done my grounding via one of the cylinder head bolts.

I hope to complete my ignition system reinstall (replacement CDI & relay) later this week and will post pictures on my Build Log.

[LA F2 Flyer]

Kurt that might actually have been your problem. Bear in mind that the engine is isolated from the adapter plate and the firewall by all of the rubber bushings used to minimize vibration.

[Mountain Cat]

Most of aircraft electrical issues can be traced to a bad ground or lack of. I always ground around the engine bushings. It does help with static interference with radios and such.