Rhus

My Dad and I were flying his e-coverted Sig Rascal 40 ARF the other day. The day was as good as they get this time of year for flying except that is was about 10 degrees F. After 3 or so uneventful flights, we noticed screwy handling characteristics during the final take off and then landed soon after. I noticed a wiggle in the tail feathers as I picked up the plane and on investigation, tail feathers came completely off the plane. Exactly how he landed the plane is somewhat of a mystery as all that was holding the feathers on was a thread of balsa. I believe that based on the clean break along the epoxy, that it was a epoxy failure and that any balsa failure was simply where portions of epoxy did not fail. I presume that the 5 min. epoxy was mixed correctly. My Dad is pretty good about mixing correctly and has a fair amount of experience building.

What is your take? I have some opinions (mainly that 5 min epoxy and 10 degree weather don't mix) but would like to hear from you all.

Thanks,

Rhus

BTW- That day was the first time I have flown a Rascal 40. That plane is seriously fun.

w8ye

My Feedback: (16)

5 min epoxy is more brittle than 30 min epoxy

Rodney

Never use 5 minute epoxy where strength of the joint is important. Not only is the probability of it being nearly polymorized before it was applied but the chains formed as it cures are much shorter (weaker) than that of the slower curing epoxies. And remember, even if the epoxy sets up in 5 minutes, even the slowest do not reach full strength until after several hours cure time, more at low temperatures.

jay2000dakota

I've had wing mounting plate come loose during assembly at the field. I figure that it happened due the shop it was built in, the temperature was changed from comfortable to just above freezing(to save on the heating bill) during its drying process. If your plane was subjected to the same temperature change durning construction, that could be possilbe cause. Ive never had a solid glue joint come loose with the planes built in my climate controlled basement and Ive flown in winter with 5 minute epoxy on tail joints. Did you brace the tails base with triangle stock? if not the vaibration coupled with the cold would crack that joint with ease

dhal22

between polyurethane (gorilla, probond) glue and hysol i rarely use epoxy. it's too sensitive to the mixture ratios. i hate soft epoxy.

TexasAirBoss

My Feedback: (22)

Epoxy and cold weather don't mix. Or I should say that heat is a catalyst for the reaction. No heat, or lack there of can result in an incomplete reaction. Cold weather can cause epoxy to take a very long time to harden.

All Day Dan

My Feedback: (5)

NEVER use 5 minute epoxy where strength matters. Always use the longer curing three hour stuff. You're lucky you got as far as you did regardless of the temperature. Dan.

w8ye

My Feedback: (16)

I don't even have 5 minute epoxy in the house

Rhus

I didn't know all the ins and outs of epoxy, but I know I work too slow to be able to use 5 min epoxy. Clearly, many of you have a pretty deep understanding of the chemistry involved. My Dad has used some on many of his new planes, and now you all have got me worrying about them too. We've had and easy 15+ flights, over the past month, on his Rascal before the problem manifest and this day was easily the coldest. It's not like we installed the tailfeathers while we were out in the cold (like someone insinuatated). I appeciate the input from all of you more experienced builders/flyers. I won't be buying any and I will relay the info to my Dad. Thanks everyone and if anyone has anything else to say, I'll be watching.

jetmech05

you must have the epoxy mixed correctly..allowed to sit while curing, and the surface prepared correctly...plus enough epoxy applied to hold the joint......I doubt you suffered a temprature related failure. I just checked a unopened pack of 5 minute epoxy...temprature range -60F to 180F needs 4 hours to cure at 72F longer if colder......
My guess is there wasn't enough epoxy or the epoxy wasn't in the right place or the surface wasn't perpared correctly...
nice find on the loose tail you saved an airplane

Rhus

I've relayed the info to Pops. We discussed your ideas. Thanks again everybody. We are both making some changes to our procedures based on your recommendations. I love this RC Universe thing. Very useful.

Roby

I am,and always have been a winter flyer for many years.

I'm not a proponent of ARF's so I know how my models
are constructed. To date I have never had a glue joint
failure due to temperature.

Regards,
Roby