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Thank's for your comments Peter. It's a tough little plane as damage is not severe. With my very limited use so far I rate it as in the same class as a Wot4 -a do everything model.

One of my clubmates had 3 lock outs with Spektrum so bought an expensive latest model FHSS/FAAST Futaba 8 channel and had a lock out on the first day using it!
Another had 3 similar in the same far part of the field with Turnigy. Two of us have now had same thing with Futaba 6EX 2,4. Spec varied, some were glow, some electric via ESC some electric via BEC. All these radios have different failsafe types. Some like my 6EX on throttle only, others have various settings.
My crash was much nearer than all the others so cannot say it was near the limit of range or vision like the others may have been. All had loss of power as first indication and then immediately lost all controls. Most of the other pilots thought they almost got radio back but too late to save the model. I cannot say I got the control back but mine was fairly low at the time so no chance. Ours is a field well away from houses and the nearest phone mast is over a mile away, but the area has recently got 4G so who knows what this might do?
We dont seem to have had any similar incidents on crowded weekend flying but from memory all the incidents may have been week days.....must check this with my pals.
Maybe I will go back to 35Mhz.....
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After further checking of the model, before repairing, I discovered that the brand new ESC has some intermittent fault which gives no current to the Rx on some occasions! Therefore I reckon the Swamp Rat problem was not due to a 2.4 Ghz problem but due to ESC lack of power to RX.

However all my clubmates problems were due to 2.4 Ghz lock outs of some kind.
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Peter, the lock outs on the crahes I observed & investigated the gear used were
3( at least) Spektrum DX8,
3 on Turnigy
1 on Futaba 6EX FAAST ( not the Swamp Rat)
1 on Futaba T8J FAAST.

Current theory is that it may be a combination of range, end on to aerial, battery running a bit low. That is when all 3 happened at the same time. 2.4Ghz takes a good few seconds to reconnect when you turn off the TX in bench tests. If all these things happened at once on 35Mhz maybe you get a slight glitch and regain control quicker and dont actually crash. On checking with a friend in Australia they suffer just like we do.

Gary,
The ESC I used was a brand new Robotbirds 40 amp bought from BRC/Robotbirds at Wings & Wheels.
I set the model up on the bench using a separate NIMH supply to Rx ....for safety of course. Maybe a longer bench test with ESC power would have shown up the problem. Regrettably I used the new ESC for 'reliability' instead of the old reliable J Perkins 35 amp I had from a previous model which was stripped of the Rx to make Swamp Rat.

Got to get back now to repairing the Swamp Rat for flying tomorrow if the weather is OK.
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Well my Swamp Rat is repaired and waiting for some good weather for another test flight.
Now it's been flown once and fully crash tested I must admit to one other modification from the original design. I used 3/16 spruce spars instead of the 1/4 hard balsa. The wing survived the cartwheel crash which ripped out the wing bolt plate and F3 before breaking the 2 BA nylon wing bolts. So I feel my use of spruce was worthwhile as the spars did not break, and 3/16 has proved adequate so far. Maybe 3/16 is marginal if the weight is greater than the 3 pounds of my version. Peter's tip about slightly rounding the spars so they fit into the ribs easier is a great idea - worked well.

I have to say also that 300 watts and a 3S2200 Lipo seemed adequate power too. No lead was needed with the layout I used - the 3S2200 balanced it well at the design CG. I must remember to check if the few dabs of epoxy to restore the ripped off tailplane and rudder have changed the CG....
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I covered just the wing then attached the front & rear fairings after they were covered. Wing covering was cut away a little to reveal bare wood to glue fairing.
It did occur to me that the front fairing could be attached to F2 if the fairing was a bit smaller. This miight be neater.
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  • 4 weeks later...

Hello fellow Rat builders,

A question for Peter -- Peter do you have any wing incidence figures for The Rat, and Harlequin?
I attach a couple of pictures of my Rat, al that's needed now is balancing & good weather for the maiden.
I shall use the new OS. 25 FP for the maiden, then if all is well change over to a OS. 25 FSR as per your suggestion.


Thanks for all the help.

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  • 1 year later...

Hi All its been a while but i have redone my swamp rat electric version after putting in the wrong inputs ,upside down and 4ft from the ground.sad

well i have changed this a little the fuselage is a little narrower and the wing profile is thinner wink 2

so i have now called it the RIZLA let me know what you think ( like or dislike )

20150903_163943.jpg

20150903_163859.jpg

20150903_164032.jpg

20150903_164022.jpg

i have a little more work to do on the cowl where the holes are will post when done thinking

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