I'm almost finished my Tower Hobby Sbach Arf. I'm powering the plane with a Rimfire .32, (recommended) and using Hitec HS-82MG 19g Servos (compatible / comparable to the recommended Futuba S3172SV mini-servos) and powered by a 4S 3600. Reading some of the stories about those who have flown or reviewed the plane, they're really isn't a consensus as to whether or not the firewall needs reinforcement. The pictures below are what the firewall looks like now. I can't discern any obvious missed areas of glue, or apparent weakness. However, some of the reviews have said the firewall needs to be brushed with an epoxy solution to add strength. This isn't a Great Planes kit, its a budget kit that I thought would give me some experience as an ARF build. Nevertheless, its a pretty airplane, and I would like it to be a longer term, rather than shorter term flyer.
Should I being trying to strengthen the firewall? I know that can add weight to the plane. Or should it be good to go like this?
the fire wall looks ok if you wanted some 1/4 triangle balsa along the inside corners and joints will add strength also ca glue all the wood joints ,using some finishing resin or thin epoxy will help harden the wood and will seep into the joints .As far as weight goes your not adding really any weight BUT DON'T GET CARRIED AWAY WITH THE GLUE OR THE EPOXY RESIN you will add weight if you go over board .your engines are electric and if your props are balanced right you wont see any vibration like fuel engines
great use epoxy to glue the triangle stock ,be careful when thinning the epoxy with alcohol ,sometimes the epoxy wont setup try some on scrap wood to see if it sets up and hardens or you will have a mess to fix ,finishing resin can be thinned with alcohol about 3 to one with no problems let me know how you make out
I was thinking about thinning the epoxy i have mixed small amounts say 1/2 oz and warm it after mixing, as long as you don't over heat it ,it will set fine and thin out so you can brush it on, i mix small amounts so you don't get a runaway thermal chemical reaction .this can happen when you mix large batches of resin because of heat build up plus your heating it with a heat gun .Sorry i forgot to tell you this the last day but remembered it now .i have done this many times to glue fiberglass tape down when joining wing halves together
Admin: I am looking for an eighty inch Cub, made by Sig. I saw one at the swap meet in London, but got distracted and it got away from me. I heard someone stole it for a paltry sum of $175.00.
Oct 29, 2019 16:48:21 GMT -5
agn: How do you get the post under " Building Tips"
Nov 2, 2019 23:03:04 GMT -5
agn: OK here goes, Dont't quite understand the process yet!
Nov 3, 2019 13:35:09 GMT -5
agn: The most useful tools I make are sanding bars. I use white pine wood of many sizes, if you have an old saw blade, cut them after gluing sand paper of different grades to the wood.Long ones short ones thin ones etc.
Nov 3, 2019 13:40:10 GMT -5
agn: I also used paint mixing sticks and broken propellers for compound curve sanding.You can use any glue but some need to be weighted to keep the sandpaper to the surface while curing/ drying.
Nov 3, 2019 13:43:13 GMT -5
agn: Also If you have a tube light , 8' is nice you can parallel the light with your work , a wing leading edge, sand and rotate it to check how the shape is working out. Longer blocks work well for this starting with course grain to finer grain sand paper.
Nov 3, 2019 13:46:30 GMT -5
don: Hi AGN go to building tips . Click on that then scroll over and create a thread.
Nov 3, 2019 19:59:06 GMT -5
les: Davis instruments has a selection of weather stations with an option for cellular data upload to the internet. $1500 US , data plan extra.
Nov 21, 2019 12:47:07 GMT -5
RICK: see if this works
Jan 7, 2020 15:55:21 GMT -5