Altimeter released glider

[roytyson]

Has anyone ever used an altimeter to release a boost glider? Seems like with an Eggtimer apogee this could be pretty simple, but don't want to reinvent the wheel if it's already been done.

 

[Ez2cDave]

Now, THAT is an INTERESTING idea !

I do not believe that has ever been done before, either !

Dave F.

 

[shockie]

I don't get it. you're going to have to provide additional information as to what problem this will solve.

 

[rharshberger]

I don't get it. you're going to have to provide additional information as to what problem this will solve.

Its just a different method of releasing a glider at apogee. Since electronics are much more reliable than motor delays, the glider would be released at apogee or so when stresses are lower and could reduce binding depending on how its mounted. IMO of course.

 

[aerostadt]

I think everyone's mileage will vary. I have launched my 4x OT sixteen times over 11 years and the ejection charge has never failed to eject the glider. That has been the least of my problems.

 

[burkefj]

Are you saying use an altimeter to fire deployment at apogee instead of the motor and the glider will come off more at optimum? Or are you using the altimeter to just release the glider at apogee and something else is ejecting the recovery for the booster?

I personally have used an altus metrum easy mini to fire deployment at apogee which in turn pushed the glider off of the model. I have not used an altimeter to just release the glider without firing deployment.

Frank

 

[Cosmoe]

I don't get it. you're going to have to provide additional information as to what problem this will solve.

There are folks out there like me who have a large number of B6-6 and C6-7 motors which are currently useless for boost gliders. This sounds like a way to make these motors useful to guys like me who love the things with wings.

 

[shockie]

There are folks out there like me who have a large number of B6-6 and C6-7 motors which are currently useless for boost gliders. This sounds like a way to make these motors useful to guys like me who love the things with wings.

so it's easier to try to figure out how to use an altimeter to detach a glider, than just break down and buy some appropriate speced motors to do the job?

 

[Cosmoe]

so it's easier to try to figure out how to use an altimeter to detach a glider, than just break down and buy some appropriate speced motors to do the job?

Yes, it's an interesting technical challenge to try to figure out how to use an altimeter to detach a glider. That should have been intuitively obvious to all but the most casual observer...

 

[burkefj]

I would think using an altimeter to fire an ejection charge at the peak altitude which in turn releases the glider is fairly obvious and easy to do. I'm not sure why you would separately release a glider at peak and not eject the recovery system for the booster and rely on a long delay after apogee to do that.

Yes, it's an interesting technical challenge to try to figure out how to use an altimeter to detach a glider. That should have been intuitively obvious to all but the most casual observer...

 

[Ez2cDave]

so it's easier to try to figure out how to use an altimeter to detach a glider, than just break down and buy some appropriate speced motors to do the job?

Of course those delays are spaced at pre-determined intervals, whereas an altimeter would release the glider at apogee, not early or late . . .

As I see it, it is more about precision of release and less stress being placed on the glider, at release.

Dave F.

 

[Ez2cDave]

The use of an altimeter for glider release is a very interesting idea. I hope that more info will follow !

Dave F.

 

[Cosmoe]

I would think using an altimeter to fire an ejection charge at the peak altitude which in turn releases the glider is fairly obvious and easy to do. I'm not sure why you would separately release a glider at peak and not eject the recovery system for the booster and rely on a long delay after apogee to do that.

Another way to bypass the problem of using motors with excessive delays would be to do what you've done with your designs. Putting the motor in the aft end of the glider negates the need for an ejection charge of any duration. I'm thinking at least some of what contributes to your success is using relatively low thrust, longer burn duration motors. When I've tried that configuration with higher initial thrust, shorter burn motors, bad things tend to happen during the boost, like looping and such. Have you ever flown an aft mounted engine glider with higher thrust/ lower duration motors successfully, or is my guess correct about requiring the lower thrust smoother ride to apogee?

 

[tab28682]

Jumping in with my opinion here.

Higher power rear engine RC RGs work fine, but you do have to have some piloting skill and experience to be successful. Definitely easier to stay with or ahead of the E6 type sport scale gliders. I have a lot of G40 flights on an older model, plus 16-20 or so F25 powered flights on a developmental Hobbylab SR-71 (normally flown on E15s).

Never had one try to loop under power. Am always very careful about the boost CG, thrust line and very careful about setup of the wings, tails and control surfaces.

People's success with higher power RC RGs is really about their RC flying skill and their skill at properly setting up a model so that it behaves well under boost when things are happening quickly.

Dave Schaefer's K powered X-2 is an excellent example of a well done high power rear engine RC RG.

 

[burkefj]

Correct yes like Tom I found higher thrust motors in rear mounted rocket gliders, for example my 4-in and 2.6 in x-15s that fly on e-20s e30s or d24s, my larger colonial viper that flies on g40s, and my wife 12 and sr-71's the fly on e-20s and e30s and f24s.

The limitation for my models is really the construction stiffness and weight if the model can handle the higher thrust motors they'll fly just fine once they're correctly trimmed for boost.

I will say in general the models don't get as high in altitude then a longer burn motor just due to drag and as Tom said the piloting skill if there's any adjustment needed under the faster boost is higher than on a slow burn motor.

Frank

Another way to bypass the problem of using motors with excessive delays would be to do what you've done with your designs. Putting the motor in the aft end of the glider negates the need for an ejection charge of any duration. I'm thinking at least some of what contributes to your success is using relatively low thrust, longer burn duration motors. When I've tried that configuration with higher initial thrust, shorter burn motors, bad things tend to happen during the boost, like looping and such. Have you ever flown an aft mounted engine glider with higher thrust/ lower duration motors successfully, or is my guess correct about requiring the lower thrust smoother ride to apogee?

 

[kkooch]

With a standard pop-pod boost glider, this idea is interesting and could prevent a red baron (glider tangling with the recovery device on the pod at ejection). Plus it releases the glider at peak apogee. I like it!

Kooch

 

[Ez2cDave]

I'm not sure why you would separately release a glider at peak and not eject the recovery system for the booster and rely on a long delay after apogee to do that.

One scenario might be a maximum-performance glider, boosted as a "parasite" to high altitude. Say, an RC glider that could "thermal hunt" and remain aloft for a very long period of time. Recovering the Booster Rocket at a lower altitude makes for easier recovery. The Glider would be released at apogee, along with a streamer or small Drogue chute on the Booster ( a dual-deployment altimeter deploys the main chute closer to the ground ).

Dave F.

 

[kkooch]

One scenario might be a maximum-performance glider, boosted as a "parasite" to high altitude. Say, an RC glider that could "thermal hunt" and remain aloft for a very long period of time. Recovering the Booster Rocket at a lower altitude makes for easier recovery. The Glider would be released at apogee, along with a streamer or small Drogue chute on the Booster ( a dual-deployment altimeter deploys the main chute closer to the ground ).

Dave F.

View attachment 465918

Dave- When will we see you at a contest? US Tryouts next year?

 

[Ez2cDave]

Kevin,

I guess you missed me at NARAM-50 . . .

Dave F.