JH Hot Deamon - a true foamboard hotliner!
- Thread starter FAI-F1D
- Start date
When it comes to laser cutting the foam board, is there a special setting on the laser cutter, and is there a risk of toxic emission?
FAI-F1D
Free Flight Indoorist
First, thanks everyone for the congratulations. I'm really happy with this model and I hope it will inspire others to give this type of flying a try. The only expensive part on this plane is the prop, but most EDF jets nowadays require batteries that cost as much as that prop, and they don't last as long (or look as beautiful!).
No, and yes. I run about 5W to engrave for score lines and 30-35W for cutting, but when I get a vacuum hold down to press the sheets flat while cutting, I'll be able to back that off to 20-25W, and possibly even less than that. You need an exhaust pipe for any real laser cutting so that smoke and fumes are directed outside. With balsa I usually leave the lid open to monitor the cutting process, but for foam I make sure it's closed up tight so that no fumes escape into the room. Foam cutting smells like airborne cancer to me...I know right away when things aren't ventilated correctly.
No, and yes. I run about 5W to engrave for score lines and 30-35W for cutting, but when I get a vacuum hold down to press the sheets flat while cutting, I'll be able to back that off to 20-25W, and possibly even less than that. You need an exhaust pipe for any real laser cutting so that smoke and fumes are directed outside. With balsa I usually leave the lid open to monitor the cutting process, but for foam I make sure it's closed up tight so that no fumes escape into the room. Foam cutting smells like airborne cancer to me...I know right away when things aren't ventilated correctly.
FlyingWithRyan
Elite member
Just found this thread now and wanted to mention that yes foam board is toxic when it burns. I believe it creates styrene gas which is toxic to the nervous system. However if you have proper filtration and exhaust it can be done safely.
What about ironing fb edges - is that an issue? It doesn’t seem like it would be since it’s such a small amount...
FAI-F1D
Free Flight Indoorist
The scaled down 50" version hit 139 mph on 6s with a GM 17x26 prop and NTM5060-380. Eventually I'll try that setup on 8s.
danskis
Master member
Ironing foamboard edges - @FlyingWithRyan - thanks for the info. I think I've already screwed up and inhaled some fumes. Not pleasant. I have no patience and I like to set my iron really high plus I like the way it forms the foamboard. I have since taken my foam outside to iron it but I don't think that's enough. Best advice is probably to dial down the iron and do it outside. You could get a filter mask but you're going to have to get one that is specific to the chemical given off.
FlyingWithRyan
Elite member
Um Im pretty sure it only releases a gaseous state at temperatures higher than what you need to iron at but the small amount isnt that bad anyway.
That's insane! I'm looking to do a 4s hotliner - what prop do you recommend? For my rimfire .15 size motor I'm thinking a 9 inch with a decent pitch will be the best option, but I can't find any good props from APC. I also don't want to spend $135 on a prop...The scaled down 50" version hit 139 mph on 6s with a GM 17x26 prop and NTM5060-380. Eventually I'll try that setup on 8s.
I did however see the APC 11x13 - what if I trimmed that down to 9 inches long - would that be a good idea?
FAI-F1D
Free Flight Indoorist
That's insane! I'm looking to do a 4s hotliner - what prop do you recommend? For my rimfire .15 size motor I'm thinking a 9 inch with a decent pitch will be the best option, but I can't find any good props from APC. I also don't want to spend $135 on a prop...
If you want a hotliner, do it right. Get a quality folding prop. You don't have to spend gobs of money though. I'd recommend looking at RFM props for an affordable option. Also, current limits are meaningless on these planes. You'll never have the prop running for more than 5 seconds at a time. Put the throttle on a switch while you're at it...we don't use partial throttle on these.
I popped together a quick ecalc setup built around your proposed setup using a set of RFM 10x17 blades. The roughly 1 minute of WOT time equates to roughly 10 minute flight times unless you're really thrashing it, and the motor would get pretty warm too. I've also used RFM 12.5x13 blades on a roughly equivalent setup and the motor stayed at a safe temperature. That change trades some top speed for acceleration. The same setup on 6s with an APC 8x10 can run pretty much continuous WOT without overheating, but the acceleration is poor.
RFM 10x16 prop (you have to go a european dealer for the 10x17, but there's not much difference): https://www.soaringusa.com/RFM-10x16-F5D-Pylon.html
RFM 12.75x13: https://www.soaringusa.com/RFM-12.75x13-Folding-Prop.html
