Estes T-25 R/C Maiden Launch Questions..

[deandome]

Maybe this weekend or next...maybe at Midwest Power...but after being completed for over a year, I finally have the nerve to fly the thing.

I'll going with an F12J reload (I made a plug for my RMS hobbyline), but I've never seen one like this go off...nor have I flown an RC plane (I'm OK on simulators, though).

Yeah, I might wanna/should have someone else do the flying for the first launch, but given that the t-25 has a history of being delicate, I don't want to put the crash-onus on someone and/or be prevented from ever trying to fly it myself cuz it crashed.

BTW, I rather ingeniously jammed some uber-strong/uber-lightweight rectangular carbon-fiber 'box-beams' down the hollow tail booms & secured w/a little Superfil...so that weakness should be mitigated pretty much. Also read up & switched out the cable elevator control w a solid control wire.

I mounted rail buttons on the bottom launch-lug 'tunnel' (very securely, into balsa blocks & epoxy...they won't flex on the fuselage), thinking/hoping that would provide torsional stability & eliminate the need for the complicated wire wing-supporters on the launchpad (do you think that'll work?).

Main question....what kind of angle, if any, do I want to have my rail set at for launch? 45 deg? Close to vertical?

I know RC cars & how NOT to over-control w/the stick...so I think I can get it going straight up after launch & then fly it in with simple turning (no aerobatics!)...am I deluding myself?

Thanks for any help/advice any of you T-25ers might afford!

 

[Serenity]

I have a T-25, and I have flown it quite a few times, including many flights on the F12J reload. I'll tell you what I do when I fly mine - this is not to say this is the only successful way to fly it, it's just what works for me.

You say that you made a "plug for my RMS hobbyline." I'm assuming this means you made something to go in the space where the delay grain normally goes. Be aware that if you are flying your T-25 at an NAR or TRA launch, an RSO might not like what you have done regarding the plug. I think that would fall under the circumstances of modifying a commercial motor, and most sanctioned launches tend to frown on that. When I fly an F12J reload, I use the delay grain, and I use the ejection charge cap - I just don't put any black powder in the ejection charge holder. Just an alternative to think about.

I use wing support rods when I launch rocket gliders. Your idea with the rail buttons may work fine, although I'm a bit concerned that if there is any wind gusts that the torsional action on the rail buttons could cause them to bind in the channel. Binding in the channel coming off the rail would be a bad thing, as it might not get up enough speed for stability when it comes off the rail. I have several rocket glider designs in mind that may use G motors, and I am tentatively planning on using rail buttons for them, but I still intend to use wing support rods. Again, just my preference.

I usually launch the T-25 at about a 45 degree angle. Then when it is about a second into the burn, I usually gently touch up elevator and bring it to about a 70 degree angle for the rest of its power climb. I think you could take it to a vertical climb, I just like the angled climb out. It lets me see any attitude changes more clearly.

One last thing - be careful and make certain not to put the igniter leads over the top of the T-tail. I saw someone do that once, and needless to say, the elevator got ripped off upon ignition, and it wasn't a pretty sight after that.

As far as deluding yourself about flying it - the T-25 won't win any thermal contests, but on the other hand, if it is built with the proper alignment, care is taken not to add extra weight, and the CG is correct, it doesn't have any bad habits.

Good luck and try to get someone to take some pics of the launch and flight. The black smoke trail from the F12J is pretty cool.

 

[JoeG]

You may do fine if you are doing ok on the simulator. That is, an R/C simulator where you are not in the cockpit or following the plane. You will be on the ground so you need to be abl to control the model from outside the aircraft. Left and right appear opposite with the nose pointed towards you.

The thing is.. the planes on the simulator are trimmed (fly straight and level with no input.) Your model may not be.

do you fly in varying wind conditions or calm weather? It could be breezy ior even gusty at the field.

You have added weight to the tail with your reinforcing. Re-check the C/G it is critical to get it in the right place.

My advice is to get someone with experience to fly it so it will survive the first flight. For a first time flier in the real world simple turns can turn into aerobatics real quick. Usually a first attempt unassisted ends in a crash.

From a long time R/C guy.

 

[chanstevens]

I recently built a Sweet Vee, and despite plenty of experience with RC boost gliders, had very little experience with "pure" R/C rocket gliders ("pure" meaning no sliding wings or shape-changing in flight). What experience I did have was rotten. Just couldn't get my head around what was going wrong quickly enough to control it, and when I did touch the controls I was overdoing it.

For the Sweet Vee, it was a very nice build, OOP model, so I didn't want to have another rotten experience. I let a buddy fly it who has extensive experience with RCRG's. He absolutely saved it--despite several perfectly fine hand toss trim flights, under power it yawed hard left and started to pitch down almost instantly. He handled it perfectly, transitioned it to glide, and dialed in the trim settings for glide. Afterwards, he helped me tweak the trims to at least make the next boost less disaster prone. I took control for flight #2 and did fine, mainly because he'd gotten most of the gremlins out from the first flight, and also because having watched him on the first one I had a much better idea of what to expect and how to react.

By the way, while I claim inexperience with RCRG's, I'm hardly a newbie on the stick--I'd logged great gobs of hours in the air training on a little Vapor plane, plus an Edmonds Arcie II boost glider. I just had no talent or experience managing that 5-10 seconds of boost.

YMMV, but I can't recommend highly enough, if there's one available, letting an experienced pilot break it in for you. Worst case, he trashes the model, which you almost certainly would have done anyway. More likely, he'll catch something before or during boost you'd have missed and helps avoid that problem.

--Chan Stevens

 

[heut]

Just a question here. See you talking about using an F12 on your T-25. I have only D11-P engines (my T-25 is not yet finished). Does any one have experience with that as well? Would be glad to know.

 

[Serenity]

The D11-P will work fine, but you will only get 150-200 feet of altitude. The D11-P gives you just about enough altitude to immediately start setting up for the landing.

 

[kooch]

I'll going with an F12J reload (I made a plug for my RMS hobbyline), but I've never seen one like this go off...nor have I flown an RC plane (I'm OK on simulators, though).

I'd recommend the D11P for a first flight. And primarily to determine that your boost trim is in order. Once you've determined this, then, yeah, jump up to an F12. When I test fly new S8's, I go with a C6, then D7 and finally E6.

If the boost trim is OFF on a lower impulse motor and the unfortunate happens, you crash, there will be a lot less damage to repair. If the trim is off even a tiny bit, the lower impulse motor will show this too, but its not going to be doing a ton of sky writing like it would on an E6 or F12.

Kevin Kuczek

 

[heut]

Thanks for the advice.