Cougar429

My Feedback: (3)

Welcome to the "Bear Pit".

It was mentioned several times here. Unfortunately the specifics may not have been.

Most of the changes were internal, but the two glass horizontal stab joiners came with thicker walls on the later versions to add strength. Just don't have a comparison or measurements. You can take comfort in that if the flutter problems are addressed the thinner tubes will likely work fine. They may not have made the effort to build better stabs in the later versions so may be necessary to tear them open to check for good bonding. ALL of the early ones were extremely substandard so even thicker tubes would not compensate for lack of bonding. the structure together. Ultracote White is a perfect match so relatively easy to get back to stock looks.

Therein lies one of the two biggest design flaws with this plane. The first is their stock elevator control system. Trying to have a tight and accurate linkage using a long balsa or hardwood rod will not really be effective. Add in the fact this plane has the least elevator deflection specs of anything I have seen, as well as the most pitch sensitivity, as well, makes for a rather bad combination. ANY free deflection of the elevators will lead to flutter Mine is currently back on the table to have smaller elevators grafted on to allow for better pitch control.

The second most obvious is their weak gear mounting. Wood is soft and not bonded on well. For reliability, especially with one with such long legs, means you need to beef that up.

Both version tubes were too long, so forcing the stab haves tight to the fuse would break away the ribs inside the stab structure. You have to shorten them a bit. Even then I found that general construction would show some gap when any portion of the stab touched the fuse. You could be a bit more aggressive when removing material at the root to get a good bond, but too much can weaken the fuse at that point. I loaded the gap with epoxy and FLOX till cured. FLOX, (Flocked Cotton) is a filler available from Aircraft Spruce that adds strength to epoxy bonds, (rather than microballoons which DO NOT!) and is sandable. First tried this when helping build a Lancair and learned to love its advantages. All my structural bonds have at least some amount added.

Cougar429

My Feedback: (3)

I sent you a PM.

Guys, as mentioned I have the bear on the table. If anyone still has the stock elevator linkage spare would appreciate the plastic bushings the rods rode in, (and then the tails were bonded into the elevator/stab). Not available in that size anywhere else.

Air Sally

I recommend open stab surgery,buy your own c/f spar as i did,and put elev servo in rear with short linkage as per my pics. I can dive wot with no flutter.

Air Sally

I recommend open stab surgery,buy your own c/f spar as i did,and put elev servo in rear with short linkage as per my pics. I can dive wot with no flutter.

Air Sally

welcome Scale guy ,great find ...must be the last kits out there , I'd love to find another F-8F kit . so many of these crashed from flutter ...I bet there are some left that the guys were afraid to build after reading this thread.

scaleCAguy

Thanks Air Sally,
I am willing to part with the F8F at the right price. I have the Rare Bear as well and not sure when I will get to both of them. If you are interested in a purchase let me know.
Thanks guys,

Cougar429

My Feedback: (3)

Aaaaaaand of course, too far away.

NUTS!

I would love to try another using all I learned from this one. I brought it to my friends jet event and still had the guys stopping by to have a boo.

scaleCAguy

Speaking of the F8F version of Bearcat....ESM makes a very nice F8F Bearcat if you are in the market for a bearcat. It is a bit larger I think than the Thunder Tiger. I have not looked at specs, but my friend flies the ESM plane with a twin DLE 40 or some other brand of gas twin 40cc. He has a newer version of Sierra Retracts in it that are stronger than the first version he said. Other than that, I have only built and flown a 1/12th scale F8F in the past that was a hand launch and flew great with an old OS .26 surpass 4 stroke. Great fun!

Air Sally

Thanks I will keep that in mind...need to sell some stuff and come up with some money . Thankfully the ESM F-8F does not seem to suffer the same issues the TT one had . thekit you have does it have a C/F wing tube? or alum ?

scaleCAguy

Mine are carbon fiber, is that good or bad?
I will trade possibly. Have any cool warbird type stuff new?

Cougar429

My Feedback: (3)

Mine also appeared to be C/F, but I found a replacement at the Toledo Show that I could guarantee was better quality. It did require some sanding to fit.

You can reinforce yours internally, but to be honest, the wing structure I saw and posted will likely fail before the tube.

New job has me working so much not a lot of energy or time to work at the hobby. Still, asking again if anyone has the elevator linkage bushings sitting in spares.

Air Sally

I had the C/F on my first F-8F it was plenty strong until the batts fell out while inverted ..... it has some cracks from the ensuing death dive nose first into the ground ..the Rare Bear I have has an alum tube that has worked so far very well too

scaleCAguy

You mean your batteries? Not clear on that. Thanks for all the info. I will be doing things much different than this kit was set up for in regards to linkages. I can seehow many got flutter due to the poor push rod set up.

Air Sally

Yeah mine was electric, there is a thread in the glow to electric conversion on RCgroups.
im telling you right now even a c/f pushrod wont work. You must move the elev servo to the rear with short pushrods.