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RocketMan3D

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Hi, I am going to enter a 1/2 A impulse glider duration contest at a local club launch. The rules allow either rocket gliders or boost gliders. I am new to gliders, so any tips would be helpful. Thanks! Rules
 
https://www.nar.org/contest-flying/competition-guide/duration-events/boostglide-duration/

There is also a Tips and Technique section on picking thermals.
Boost gliders shed the motor so usually have longer durations. Rocket gliders retain the motor so you have to change the model's configuration to swing wings, shift motor to change C/G, unfold wing segments, etc. So the latter are more complicated.
It also depends on the motor impulse that is being required. "A" and below usually use 13mm.

https://www.asp-rocketry.com/ecomme...-Kits-from-other-Manufacturers.cfm?cat_id=132

https://www.apogeerockets.com/Rocket-Kits/Glider-Rockets

There are other vendors, but these two come to mind.

Chas
Flying competition since 1968
T-201 Pod Bay Doors Team
 
What sort of glider are you thinking about building? Or do you already have one? It would be silly for me to say I favor rocket gliders, since that's just because my eyes can't work independently and follow two objects at once. I've done a bunch of free flight catapult gliders and one sliding wing rocket glider, a slightly modified Fliskits Nano. A nice feature of a sliding wing rocket glider is that you can set it up with a larger static margin* than a catapult glider, because the sliding wing means you don't have to worry about looping. With a catapult glider, it needs to be close to the edge so it won't loop at higher speeds, or some gadget to prevent it. With the sliding wing, you're all set. Particularly if you set it up so that the wing has a VERY SLIGHTLY lower incidence in the back position during boost.

It might be a good idea to make a free flight glider to practice trimming with, as you can have a flight every couple of minutes, for free. It can also be a hack job to practice building with. Here's a simple one: https://outerzone.co.uk/plan_details.asp?ID=3756 If you want to sand in an airfoil, go ahead, but for learning how to trim. I'm not sure which type of glider would be easiest to launch.

When building, use c-grain (aka quarter sawn) for the wing and tail surfaces.

Gotta run. I'll have more later, particularly if you remind me.

*cg further forward compared to something called the "neutral point"
 
Thanks! I think I am going to build this one. Just one question: when trimming the glider, would I be able to toss it like a free flight glider?
Yes, see the links other people sent for trimming tips.

My competition days in the early 90's took place when I lived near Syracuse NY. I've been in Las Cruces, NM for 20+ years now.
 
Thanks! I think I am going to build this one. Just one question: when trimming the glider, would I be able to toss it like a free flight glider?
Yes, but if you throw it with any force, it should try to loop. In other words, a conservative cg and enough up trim to fly reasonably slowly. At least if that doesn't screw up the launch.

A canard won't get quite as much time as a conventional configuration, but may be easier to trim*. Plus a glider with ordinary performance, flown by someone who knows how to pick thermals, is likely to outperform a really good glider flown by someone who doesn't pick thermals well. It was more luck than skill, but I had a two minute flight with a Sparrow (see link in my earlier post) that was shrunk to 10 inches span and converted to "catapult" launch. If you get any good at this, you may find yourself wanting a "DT", which makes the glider come down quickly after a certain amount of time. I've lost several gliders to thermals.

There is some glider info here:
https://www.freeflight.org/docs-category/technical-library/

more here:
https://amaglider.com/

I suspect most good catapult gliders can be converted to boost gliders. They already have hooks, which might even be in the right place. And converting a hand launch glider to a catapult glider is pretty easy, too.

The flight trimming advice for the glide will be relevant to you, probably for any type of free flight model that has a glide phase. The techniques for coping with the launch, not so much.



*The only canard I've made was an old style twin pusher, which was very easy to trim, despite having two propellers.
 
What sort of glider are you thinking about building? Or do you already have one? It would be silly for me to say I favor rocket gliders, since that's just because my eyes can't work independently and follow two objects at once. I've done a bunch of free flight catapult gliders and one sliding wing rocket glider, a slightly modified Fliskits Nano. A nice feature of a sliding wing rocket glider is that you can set it up with a larger static margin* than a catapult glider, because the sliding wing means you don't have to worry about looping. With a catapult glider, it needs to be close to the edge so it won't loop at higher speeds, or some gadget to prevent it. With the sliding wing, you're all set. Particularly if you set it up so that the wing has a VERY SLIGHTLY lower incidence in the back position during boost.

It might be a good idea to make a free flight glider to practice trimming with, as you can have a flight every couple of minutes, for free. It can also be a hack job to practice building with. Here's a simple one: https://outerzone.co.uk/plan_details.asp?ID=3756 If you want to sand in an airfoil, go ahead, but for learning how to trim. I'm not sure which type of glider would be easiest to launch.

When building, use c-grain (aka quarter sawn) for the wing and tail surfaces.

Gotta run. I'll have more later, particularly if you remind me.

*cg further forward compared to something called the "neutral point"
Good luck finding C grain... SIG maybe? Hobby lobby and such does not have it.
 
Hi, I am going to enter a 1/2 A impulse glider duration contest at a local club launch. The rules allow either rocket gliders or boost gliders. I am new to gliders, so any tips would be helpful. Thanks! Rules
Easily the most reliable, simple to build glider kit out there, and it puts in some surprisingly good duration times (Condor, sold by Apogee). https://www.apogeerockets.com/Rocket-Kits/Skill-Level-2-Model-Rocket-Kits/Condor-Boost-Glider
I always keep one in my fleet, as I've lost three over the years on just B motors.
 
Good luck finding C grain... SIG maybe? Hobby lobby and such does not have it.
The LHSs that I check have the old SIG bins, but they have not been restocked for years. The lat time I visited Hobby Lobby they had some excellent Balsa in stock. I have not been building much, and I may have a lifetime supply already, mostly SIG from better days.
 
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Thanks! I think I am going to build this one. Just one question: when trimming the glider, would I be able to toss it like a free flight glider?
Hi, My choice in glide-trimming is to find a playground with something you can climb up and toss your glider from at least 10feet or higher at the "toss height" and toss the glider level or s-l-i-g-h-t-l-y down. If you get the launch part fairly straight up, you should have enough height and speed that your glider will find a level flight path on it's own once you get the trimming correct from the playground tower. Given that everyone here has good tips for trimming, I agree with them, but there's also personal preference for inducing a circling/turning path. I much prefer tilting the Horizontal Stabilizer/elevator or Canard instead of using the rudder as I get better launch trajectories that way.

You "can" do the FF glider near-vertical toss for testing, but with rocket boost gliders, I get better results with the playground tower toss method.

Also, if you're going to be "competitive", be sure to take your time and put a good airfoil on your wing. I would recommend also putting thin CA on the leading and trailing edges of the wing, elevator and rudder - if you really get into it, putting hardwood leading and trailing edges on prior to sanding will make a much more ding-resistant glider, especially if you end up with really low density "contest balsa" (think Bud Nosen brand balsa). However, if you're competing with a bunch of other newbies, chances are that just have a well trimmed glider that glides nice and floaty in a circle without diving, spiraling, stalling, etc without any airfoil has a better chance of winning than a well built but badly trimmed glider, or badly built (and badly trimmed) glider.

Hope that 's of some use, good luck! -Paul
 
Seems like it would be extra trouble for them to sort out and remove the c-grain, unless they were selling it to some other company.

They don't sort it out. I doubt anybody at Hobby Lobby even knows what C-grain is. It is profitable to sort through the balsa armed with a scale and a density table looking for good wood.
 
If are just getting started the J and H kits are a great way to go.
They don't sort it out. I doubt anybody at Hobby Lobby even knows what C-grain is. It is profitable to sort through the balsa armed with a scale and a density table looking for good wood.
Take a look at specialized balsa they sell by grain and weight.
 
Easily the most reliable, simple to build glider kit out there, and it puts in some surprisingly good duration times (Condor, sold by Apogee). https://www.apogeerockets.com/Rocket-Kits/Skill-Level-2-Model-Rocket-Kits/Condor-Boost-Glider
I always keep one in my fleet, as I've lost three over the years on just B motors.

But will that fly with 1/2A motors? I didn't see that in the motor list for it.

I just found one of those I did not know I had in my stash last week when looking for things I had extra to sell.
I moved it to the "I'll keep it pile"
 
Good luck finding C grain... SIG maybe? Hobby lobby and such does not have it.
Easy Built lists it. I seem to remember there are one or two other sources that do, in addition to Sig. I've bought c-grain from Sig before.

With an appropriate saw, it's possible to cut c-grain sheets from balsa blocks.
 
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They don't sort it out. I doubt anybody at Hobby Lobby even knows what C-grain is. It is profitable to sort through the balsa armed with a scale and a density table looking for good wood.
I've done this many times, though not at Hobby Lobby. It might be a good idea to take something that measures thickness, too. Thickness varies enough to make a significant difference, sometimes in the same sheet. A slightly thicker sheet that weighs a bit more may actually have a lower density than a thinner sheet that weighs less. I used to make a habit of taking a small postal balance and a calculator most times that I went to a hobby shop, back when we had those.

Balsa also varies significantly in stiffness, in case one wants to build an especially thin wing or just drive oneself nuts. More detail can probably be found at Indoor News and Views. I used to use a known weight and measure deflection, but there's an easier method that uses buckling and a scale. But that might be too much trouble for most wings. I did this when I was building models for EZB, an indoor event for very light rubber powered model airplanes. Stiffness to weight was a huge part of it. It's not "EZ" to be competitive in that event at all.
 
If are just getting started the J and H kits are a great way to go.

Take a look at specialized balsa they sell by grain and weight.
I HIGHY recommend J &H Aerospace kits as well, their balsa selection in their kits that I've built (or sitting in the packages waiting to be built but opened and inspected) has been TOP NOTCH!!!! This makes sense since they compete in freeflight events where it really counts and ability to read and sort balsa is a must.
 
But will that fly with 1/2A motors? I didn't see that in the motor list for it.

I just found one of those I did not know I had in my stash last week when looking for things I had extra to sell.
I moved it to the "I'll keep it pile"
This one is for smaller motors, the condor is too big for a 1/2a - it has an 18mm mount.
This is the one you want, perfect for 1/2A3-2T 13mm motor.

https://www.apogeerockets.com/Rocket-Kits/Glider-Rockets/Mini-Condor-Boost-Glider
 
Everyone always forgets the 1/2A6-2.

kj
True, but for sake of this thread a smaller glider designed for mini engines would be better, the other one is more suited for B-C motors... and it is cheaper too.. Once you have one you can keep the plans and scratch build another one scaled up bigger for cheap...
 
Wow, they have the Mini Dactyl on page two , those were always fun. Not really competitive with the top fliers but got qualified flights that just might place above those with better gliders that have problems in boost and not qualify.
Neat little glider. It was competitive during the days when you had to "fly the field." Biggest problem with these is they tend to fly out of sight quickly. It's no good to have a competitive bird if the timers can't see the glider (under NAR rules - no binoculars) after 60 seconds. But I do agree with you that the Mini Dactyl is at least a reliable qualifier. This glider could be a dark horse in a contest populated with top fliers.

I'd go with a more conventional glider.
 
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