Get your model airplane back! Dethermalizers for free flight airplanes

A commentary on various recovery methods (dethermalizers) for rubber powered model airplanes, but scale and endurance. Find dethermalizer fuse, lighters, and viscous fluid timers at volareproducts.com. Clockwork timers available at texastimers.com. Electronics timers are available from Stevens Aero.

[@johnwhalley4217]

hi mate I'm in England where can I get these quick-release things from as i am only got small areas by then and i am just returning back to the Hobby after 30 years now I am 62 cheers John😀

[@joshuawfinn]

John, in the UK you should be able to get button timers at freeflightsupplies.co.uk

[@monkfry]

Josh, I think you missed the most popular setup for beginners. I was taught at a young age to light the fuse and throw it as quick as possible. Before it explodes. It was Very effective as the planes always came down pretty darn quick. I tried the fuse method you were showing a couple of weeks ago when I was visiting down in CA. and now everyone’s mad about the smoke, evacuating, looting etc. .

[@jimbo2629]

Here in England the tip up tail is the most popular. Wing DT is more efficient. Hardly anyone uses a fuse, most use a Tony timer. The viscous timer is lighter but less reliable. Competition fliers mostly use a radio DT with a tiny servo. This has several advantages, including the ability to avoid disaster.

[@josephfreeman5289]

I was watching your videos and wondering how these worked. Was going to ask but I found this! Awesome stuff Josh! thanks you!

[@NemoVir]

So, the better you make the model. The more likely you will lose the model.

[@MartyLJ57]

The last option seams to be the way to go, for a beginner.

[@aztec-Tv22]

I am interestes about the fuse mechanism...how to get the derail about it. Any reference fir me?

[@joshuawfinn]

Faimodelsupply.com sells the fuse. You just use a rubber band to hold the dethermalizer surface down and lap it across the fuse. Light the fuse and wait.

[@scottcummings8074]

Need to build a rc dt. Just push a button and bring it down. Lush the button again to recover from fast decent.

[@edsmith7477]

Josh There is one method I have used you overlooked in your presentation . If interested pls contact me.

[@joshuawfinn]

Shoot me an email at [e-mail]

[@georgesmith4509]

thanks!! now retrieving my free flight glider makes sense I had no Idea what thermaliser was. And thats after building (and losing) lots of free flight planes.

[@lr21643]

Enjoyed the video. Have watched several of yours. Wondering what happens if, with the pop off wing, you attach the line to the center of the wing. Seems like it would be significantly less drag without that line being pulled diagonally through the air. Also, I wonder if people have tried any of the following to bring the plane down: -hard-over rudder -lots of down elevator -hinging the stab at, say, 25 percent of chord and fastening the front part permanently to the fuselage, with the rear part popping up for DT -Braking the prop so that it spins somewhat slower than when freewheeling. Maybe a magnetic brake would do the job, and maybe all the DT stuff could be concealed inside the model. Once, when I was flying at a small field, I tied down the freewheel so that the rubber eventually stopped the prop. This threw the plane out of trim and made it come down a lot faster. Not enough to cope with a strong thermal or anything, but it kept the model on the field that evening. I built a twin pusher without any freewheels. It comes down pretty well once the props stop. It will do around 90 seconds if everything is just right, even though it's all sheet. Maybe more if I worked on optimizing the motor size. (Julius Unrath's Flying Aces Twin Pusher, can be found on Outerzone)

[@patriotrob7066]

Did u say p30?? I bought a free flight plane at a swap. The box says p30 climax... super cool plane.. round tube fosaloge. Also I have a nitro free flight plane from the 40s.. It has a fuse tube. But it also had a DT timer at one time. Were can a guy find one?

[@joshuawfinn]

Climax is a good plane. Times can be had in limited supplies at texastimera.com. fuse for dts is available at Volareproducts.com or faimodelsupply.com

[@xzqzq]

Joshua: I am mulling how to rig a DT on 48" foam gliders from Walmart. Thinking of launching them from @ 5K ' AGL, with a High Start....Perhaps turn the rear of the horizonal stab into a spring-loaded elevator, as large as possible. Thanks

[@joshuawfinn]

Honestly sounds like you're on the right track. Tail pivot is the way to go, using either a rotary damper timer or a BMK radio timer. I actually sell both of those now, or you can source the bits from a variety of vendors.

[@TroyBallard]

Wow, this was so informative. Great job! I am putting a wing pop up DT, like the one on your Maxout, on a HLG. I have no idea how this will behave at different pop-up angles. It looks like you are at ~45 degrees. Have you played with this angle and what works best for you?

[@joshuawfinn]

Troy, for gliders, go to a full 90 degrees of the plane will accommodate it. That's what we're doing on all of them now.

[@davidpowell5437]

That was a great exposition of a subject that I didn't even know existed - but Goodness Me! Burning fuses and paper skinned models - I'm struggling to understand why none of your aircraft have scorch marks!

[@joshuawfinn]

The fuses are isolated from the airframe using the aluminum tubes so very little scorching occurs. They're surprisingly safe!

[@cateyesaerial7703]

I need to do this!

[@nhschreiner]

Very enlightening.Where does one purchase the small viscus timer?

[@joshuawfinn]

I actually sell those and several other types of timers now: jhaerospace.com/product-category/building-supplies/dethermalizers-and-timers/

[@robertbrunston5406]

Thank you for sharing your very good technical information!

[@frogsoda]

Hey Josh, I didn't know what a Tommy timer was so I looked it up, and it's a little wind-up toy. They sell these little wind-up cars at the dollar store, for a dollar. Would those timers work, do you think?

[@joshuawfinn]

You'll have to cut off all the car and such and add weights to the regulator/escapment (which is what we do anyway), but so long as you can do those things, it should work just fine.

[@cattaraugustonawanda4426]

FF beginner building an embryo What are useful sizes of rubber bands? Sure would like to see drawings on how to set these up !

[@joshuawfinn]

I recommend using 1/16" supersport rubber. I really have not liked using commercial rubber bands for anything on my planes. They tend to crush stuff over time.

[@khalidtarawneh2289]

thats was worth the watch, very informative thanks would like to know if there is a source i can get the viscous mechanism from Cheers

[@jimeagle1]

See /Building Supplies/free flight glider parts on Josh's jhaerospace website

[@barrystevens2780]

Years ago with larger free flights we used a spring loaded air pot that cut the power for a battery ignition engine.

[@joshuawfinn]

I've got a few of those. John Tatone introduced his mechanical timers after losing a major contest to the unreliability of those old air timers

[@nathanielpea5819]

Are you OK to ship a viscous doodad to the UK? Tia

[@joshuawfinn]

Yes we can do that. Check freeflightsupplies.co.uk first to see how their prices compare, might save some on shipping

[@nathanielpea5819]

@@joshuawfinn thanks for the tip! I've actually been stalking their site for a few weeks now. I'm really a plastic kit bloke, so a newbie at aero modelling. Free flight supplies is very much for those in the know! You also have some items that your site has and I can't find here, so I'll probably wait a bit and put a worthwhile package together. Probably a short kit and some tools as well. Again, thanks for the info. All the best.

[@RCAeromodels]

Hi Josh, very very informative videos, like it too much. Where can I get these dethermalizers, please give me link.

[@joshuawfinn]

Mannish Boriikar volareproducts.com has all of the systems shown here except for the clockwork timer which is no longer available.

[@eteet]

Hey Josh, what is that white mid-wing model at 2:20? Me likey!

[@joshuawfinn]

It's a semi scale Heath Midwing from Lawrence Smithline's plans. Flies great!

[@AeroCraftAviation]

What is the flying weight of that mustang? And where'd you get the kit? I just finished the guillows P-51, and it came out to around 28-30 grams, depending on the size motor I use...

[@joshuawfinn]

Copterdude it's about 25...20g airframe, 5g of rubber. could probably take a little more. yours is a good weight, especially for a guillows build. mine is based on the Peck peanut mustang blown up to 17.5" and modified beyond recognition.

[@AeroCraftAviation]

Did you do any other flying of that model other than in the video you posted? If so, how long were you able to get it to fly? I wonder because I'm somewhat of a begginer to scale rubber power, and want to know what to expect from my mustang.

[@joshuawfinn]

Copterdude, no other video. it does about 45 seconds on average. I need to work with it more because it should fly much longer than that. probably need to add more power. it's flying on 4 strands of 3/32 at the moment.

[@56Seeker]

Nice video, thanks. Links to suppliers of fuses, viscous timers and similar would have been nice in the description.

[@joshuawfinn]

Thank you. I'll work on doing just that!

[@wdtaut5650]

10:56 "What you really want to use here is a spring (to have a longer run time)." What is the advantage of a spring to a rubber band? Couldn't the rubber band length/width be adjusted for different tension (thus varying the run time)?

[@joshuawfinn]

WDTA UT, yes a rubber band can do that, however it will deteriorate over time whereas a spring, so long as the model is stored in a dry environment, will not.

[@wdtaut5650]

Thanks, I see your point and agree.

[@soklina5787]

So good how much sir

[@keithmccormick1272]

ARE YOU GOING TO HHAEFI ? HOPE TO SEE YOU . YOU KNOW I COULD NOT DO WHAT YOU DO WITH KZbin VIDEOS . THERE ARE FAR TO MANY DISCONTENTS OUT THERE . YOUR DOING GREAT KEEP IT UP . HI TO YOU AND THE FAMILY . I USE CAPS EYE TROUBLE ..

[@joshuawfinn]

Keith McCormick we'll be there! Looking forward to seeing y'all!

[@keithmccormick1272]

@@joshuawfinn THATS GOOD NEWS I WILL TELL LYNN .

[@robertlundstrom8061]

Is the viscous fluid timer something you build or buy?

[@joshuawfinn]

You can build a type of viscous timer with silly putty, but I recommend buying them from volareproducts.com. :)

[@vintagebalsa6440]

Good vid. What size is the chaimbermaid and did you modify that wing?

[@joshuawfinn]

Span is a little under 18", from a scaled down Henn plan. I did modify the wing into a cracked rib arrangement and put in some geodetic diagonals to compensate for the reduced stiffness in the wing center section because of the clipped trailing edges. The DT setup is based off of Bill Henn's setup. I seem to remember that his article in Free Flight Quarterly detailed the DT arrangement.

[@vintagebalsa6440]

Thanks.

[@sandfac3427]

Very helpful, thanks for sharing.

[@joshuawfinn]

Glad to help. Hopefully you can use it to help your embryos stay around a little longer. ;)

[@Astracygnus]

Love your videos. Can you make a video about how to make a stab or wing pop up setup? Do one need hinges or something similar to hold stab or tail in place when it pops up?

[@joshuawfinn]

Abid Hussain I'll have to do that at some point. No hinges are required. It's all rubber bands and a line that limits the travel. The technical library at freeflight.org has several diagrams showing different methods for dethermalizers.

[@Astracygnus]

@@joshuawfinn Thank you

[@jlehman1293]

what would be the slowest flying rubber model for outside

[@joshuawfinn]

j lehman for outdoor flying it's hard to beat a good P-30 for slow flying, especially on two loops of 1/8. Boomer by CB Models is excellent, also the Airshark by Starlink-Flitetech. Coupe/F1G models fly quite slowly too, but require a little more support equipment and space.

[@joshuawfinn]

I'll also add that the new Small Mulvihill models glide at little more than walking speed. They can cover a lot of ground, though--no minimum weight for competition, and 20g of rubber mean flight times over 4 minutes are the norm.

[@iamanon4u]

Very cool! With a good D/T I found I was less afraid of really packing in the winds. I make my own electronic D/T and have gotten them to be extremely reliable. I put them on everything including peanuts that I fly outdoors.

[@joshuawfinn]

DTs really do change the game!

[@TonhaoMastersBR]

Josh, Im a FF beginner and would like to know... how do you make the stablizer type DT? I Could observe that the fuselage and the stab are tied by a rubberband. But do you do it? And how to insert the fuse in the fuselage and burn it (the dt fuse) without damaging/burning the fuselage???? Sorry for só many questions. Thanks!!

[@joshuawfinn]

Stab DT's are easy. You have a pair of hooks on top of the stab so you can secure the front of the stab with one rubber band and the other by either a line running forward to a rubber band, or a rubber band running to the back of the fuselage and a fuse. Look in the technical library at freeflight.org for more cool ideas there. Now the fuse install question is an extremely important one. You don't just want the fuse to not burn the airplane, you want something to actually extinguish the fuse once it's done burning the rubber band. I do this by cutting a piece of 3/16" aluminum tubing to about 1/2" long and flaring one end (actually flare the end before cutting to length--easier that way). You sheet in the area you want to mount this tube with 1/16" sheet, and then drill the hole for it after covering the model. Flare the hole slightly so you can flush mount the tube. I use CA glue, but bear in mind that you need a tight fit since the CA liquefies everytime you use the fuse, so there's a period of about 90 seconds during which the tube is a little loose and could reposition itself (also, don't touch the tube during this time--it's HOT!). Anyway, when the fuse burns down into the tube, it is snuffed out by the lack of sufficient air supply. Once burned out, you just poke the remaining bits out with a piece of 1/16" wire and insert a new fuse.

[@TonhaoMastersBR]

joshuawfinn Thanks Josh, Im gonna try it on depron fuselage first!!! :)

[@joshuawfinn]

Cool. Add a wood insert for the tube to mount into since it'll melt straight through the depron otherwise.

[@TonhaoMastersBR]

joshuawfinn But Josh, what I have here is Not aluminium, Its scrap metal tube (low quality metal tube), does it work?? And you mean putrefação a piece of balsa beterraba the tube and depron, right? ??

[@TonhaoMastersBR]

The correct name is brass metal tube that I have here. Sorry Im brazilian, some words I have to search. Will this brass melt?

[@brianpercival1829]

When I was a kid, my Dad made Free Flights with Cox .020 and .049 engines. This was in the 1960's. The simplest thermal fuse was a brass tube in the tail halfway between 2 dowels. The stabilizer and Fin/Rudder had a dowel in the center of the stab. Another dowel was at the bottom of the fuselage. The brass tube 1/8" diameter about 1/2 inch long and a tiny elastic band over the 2 dowels. It was twisted so the band was tight against the exposed fuse. It would release after a few minutes flight time. The tube made the fuse extinguish when inside the tube. The examples you have showed look complicated and the viscous dampers only last a few seconds.

[@joshuawfinn]

Brian, it's 2020 and reaching all the way to the back of the plane to light the fuse is a great way to damage a fully wound airplane. On lightweight models, popping the tail won't bring the airplane down reliably. I don’t know how you're setting up viscous dampers but you're doing it wrong. They're good out to at least 4 minutes.