Tech One/Nitroplanes Popwing RC Rocket glider conversion

The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

tab28682

Well-Known Member
TRF Supporter
Joined
Jul 29, 2014
Messages
2,114
Reaction score
715
Picked up one of the little EPP foam Popwing gliders on the free shipping sale over at Nitroplanes.com. Some versions of the kit are on sale for as little as 29.95.

Decent amount of carbon structure in the wing makes it fairly stiff for hot wire cut EPP. Certainly robust enough for 18mm BP motors.

Wingspan is about 24" and it looks like it will convert nicely for C6 rocket power and weigh in close to 4oz.

Planning on insetting the 18mm motor mount tube as far forward in the wing as practical to keep the CG shift to a very small amount and to keep the thrust on the center of mass.

More as it comes along.

image.jpg
 
That looks like it'll make for a great conversion.

FWIW - here's a page and info on conversion of a 48" span "Zagi", which flew on 32mm reloads (F13 or G12). A lot more expensive to fly than the PopWing.

Ironically, 2 years ago I converted it to electric power. Flew very nice, but I made a mistake and crashed it. Broke badly at the root due to the cut-outs for the engine mount and the noseweight. Eventually I'm going to rebuild it, but will remove 2" in the center to get a 100% strong clean joint, and only fly it on electric power.

https://georgesrockets.com/GRP/GLIDERS/Zagi.htm

Zagi_Rocket_Conversion.JPG
 
Last edited:
At least on rocket power the thing won't have that awful Zagi whine. The prop is too close to the TE and back in the NiCd days of electric flight when the things were pretty popular they were the noisiest things in the air at an electric airplane meet - by far!
 
The Popwing is almost done after just a couple of hours of work.

The 18mm motor mount is in place and neatly faired in with a card stock fairing. Will be easy to swap back and forth from rocket to electric power.

Servos, linkages and RX battery are installed. Just need to borrow a micro RX from some other model and do the final CG and control adjustments adjustment.

Pictures coming soon, although I am heading off to DC for work untill Thursday.

This does end up being an inexpensive model. 30 bucks for the kit with free shipping about 8-10 bucks for the two servos, about 6 bucks for a Spektrum compatible RX and a small lipo that is under 5 bucks. Motor mount from the misc rocket parts box. Just over 50 bucks total
 
This does end up being an inexpensive model. 30 bucks for the kit with free shipping about 8-10 bucks for the two servos, about 6 bucks for a Spektrum compatible RX and a small lipo that is under 5 bucks. Motor mount from the misc rocket parts box. Just over 50 bucks total

What servos and receiver are you using for this?

Of course it is a relative, no need for an expensive receiver with 3/4 mile or more range for a model that may never fly 1/4 that distance away (have had bad experiences with very cheap receivers at ranges less than they should have been good for). Sort of same for servos, in a small model that is robust and mostly ARF so if a too-cheap servo goes bad it would not be as devastating of a risk for a model that cost more and/or had lots of time put into it.

I had a cheap very small Hobby King servo go dead on me, in a contest type model (B & C powered) that did have a lot of time into it (homemade composite vac-bagged wing). The good thing is that the servo did not go dead in flight. I replaced both servos with Dymond D-47's, even though they did stick out into the airflow some (servos in wing). I know there has to be some reliable enough cheaper servo than D-47's (about $20-ish IIRC) for this kind of flying though, so that's part of why I'm asking.

- George Gassaway
 
George, what did you use to prevent the motor exhaust from scorching the wing? And, FWIW, I've had excellent results using the Towerpro SG92R servos. Not one has died on me yet, aside from crash damage...
 
What servos and receiver are you using for this?

Of course it is a relative, no need for an expensive receiver with 3/4 mile or more range for a model that may never fly 1/4 that distance away (have had bad experiences with very cheap receivers at ranges less than they should have been good for). Sort of same for servos, in a small model that is robust and mostly ARF so if a too-cheap servo goes bad it would not be as devastating of a risk for a model that cost more and/or had lots of time put into it.

.....

- George Gassaway

Not all inexpensive RXs and servos are created equally. There are some real bargains to be had in some very good units.

I mostly fly electric RC models these days and have about 80 flyable models at any given time. Some large models, more medium and small and micro models.

My go-to RX for small sport models and Parkflyers is currently the Lemon 6ch DSMII Spektrum compatible RX (not a clone RX. Different design than Spektrum) I buy these 5 at a time for about $30.00 shipped from the factory in Hong Kong. Quality of the build is excellent under a microscope.

The Lemon name is misleading. They chose that name to compete against a clone RX maker called Orange.

I have around 16-18 Lemon RX units (around 12 of this version) and they are all working flawlessly for me. They are also very well reviewed by many over on RC Groups.

https://www.lemon-rx.com/shop/index.php?route=product/category&path=59

I also use 20+ Orange 610 and 615 six channel RXs and I have had just one go bad.

My failure rate on genuine Spektrum RX units is a little higher than I am seeing with the inexpensive units.

I have lots of HXT-900 9 gram servos, lots of HTX-500 5 gram servos and a good number of Turnigy sub micro servos in the 3.6 to 4.2 gram sizes obtained from HobbyKing. All are giving excellent service.

Again, I have had more issues with name brand servos than I have with the low cost units.

Before buying low cost units, it is a good idea to do some research and see what is working well for folks.

There are some suppliers of counterfeit RX units that you should stay away from.
 
George, what did you use to prevent the motor exhaust from scorching the wing?

On the Zagi, it is a couple of peices of aluminum tape, as used for heating ducts or sometimes in a fix on car mufflers. Thicker than cooking foil, and has a sticky backgin on it. I have used that on the top of various glider wings to prevent scorching. But on that particular model, it got almost no damage anyway because the F13/G12 reloads burn very clean. A D12 for example would probably have worn out the tape after a few flights.

Tom, thanks for the info on the receivers and servos. That's why I asked, as I knew you would not risk using something of poor reliability just to save some money.

I have heard of the Lemon Rx's, have not tried any. Wish I could say the same for the Orange Rx's. Too many crashes before realizing they were the cause, now the only time one gets used is for some cheap simple project that's not going fly more than 300 feet or so away, or not be a big deal if it crashes.

Actually, there is one Orange Rx that worked out well, and ironically it is a very small light RX, was used in some B Boost Glide R/C gliders, which are too small to visually allow to let fly very far to begin with.

My favorite small Rx is the Spektrum AR-400, about $30. With the case off and pins shortened, it can fit iside of a wing, and weighs something like 3 grams. I've had a Radian as far as about 3/4 mile away.... which was not the plan but I was playing "chase" with a PD model, later trying to hit the PD model to try to snag it (our own team's model), extreme longshot, and came to realize wow was the Radian far away and time to come back. But for the most important models, Spektrum AR-6250 receiver (stocked up, have not used its replacement yet). Before the big switch from 72 mHz Futaba 8U to 2.4 Spektrum, I was using Hitec micro receivers, 555's I think.

- George
 
Word of advice: you need to be really careful with 18mm BP motor R/C gliders. My brother and I put 10 motors through mine at one launch! They really suck down the propellant! :wink:
 
Word of advice: you need to be really careful with 18mm BP motor R/C gliders. My brother and I put 10 motors through mine at one launch! They really suck down the propellant! :wink:

Well, that's a "Good" problem! When I was helping to teach Zack Stenberg to fly R/C R/G boosts, one day we were at a park with "Redwing", first crude prototype Raven-10 by Bob Parks. His son flew it as his first R/C R/G, then it was passed on to more newbie fliers. IIRC Alyssa Stenberg was the 3rd Junior newbie to fly it and Zack was the 4th, (Brendan O'Bryan was the 5th). It is quite literally a flying baton to be passed on to the next junior who wants to learn to fly S8D. Pretty much donated by Bob Parks as a "pay forward" model whose only cost is to pass it on to the next prospective Junior S8D pilot to learn to boost with, and the next, and the next.

Anyway, in about 2.5 hours, Zack made 30 boosts on it with C6-0's. Redwing itself is sorta heavy and draggy, so it does not boost as well as the refined contest-worthy Raven-10's, or glide as well. But still, a nice model to get in first R/C R/G boosts with (He had done an R/C B/G first, but it had a Spooler Pop-pod and he didn't really need to pilot the boost).

At least with today's R/C gear size and mass, it is not too hard to have nice flying models powered by C6's, or even B's with the WhipIt conversion that Tom.... "whipped" up...... When I made my first R/C RBG flights, they were with D12 power. Same desire to make lots and lots of flights, but at the cost of D12's rather than C6's. Of course the cost of the radio gear was way more expensive than today, and much heavier (and using balsa wings!). Several flying sessions of 10-12 flights, often ending because I ran out of D12's.

- George Gassaway
 
Last edited:
On the Zagi, it is a couple of peices of aluminum tape, as used for heating ducts or sometimes in a fix on car mufflers. Thicker than cooking foil, and has a sticky backgin on it. I have used that on the top of various glider wings to prevent scorching. But on that particular model, it got almost no damage anyway because the F13/G12 reloads burn very clean. A D12 for example would probably have worn out the tape after a few flights.

Tom, thanks for the info on the receivers and servos. That's why I asked, as I knew you would not risk using something of poor reliability just to save some money.

I have heard of the Lemon Rx's, have not tried any. Wish I could say the same for the Orange Rx's. Too many crashes before realizing they were the cause......

- George

George, what was your sample size on the Orange RXs? Typically, they tend to work well, with the occasional dud. I always range check them (all aspect, moving the model around to see if any position shadows the RX.) I have had zero failures with any Orange RXs that passed the power up and binding, plus the range check. The one dud I had would not bind.
I have had to reposition a couple of Orange RXs when the small antenna was shadowed by a lipo battery or by too many servo wires near the antenna in a FW positions.

Lots of threads discussing the Orange RXs over on RCG and the threads are quite positive. A few bad ones are reported, but only a few. I also have one of the very tiny 4ch Oranges in a 35mm EDF model and it has also worked well.

I started using the Lemons based on very positive reviews and on the fact that the Orange 6 channel went up in price to about 10 bucks. The Lemons are a bargain at 6 bucks shipped in quantity. I find that DSMII works fine for me in 99 percent of the flying situations I am in. If I were going to be at a very large RC event (150 plus pilots), I would always fly medium and larger models on DSMX to avoid any issues with tons of TXs being on at once. Not so worried about small lightweight parkflyers being flown close in.

The explosion in small electric models over the last 15 years has certainly had beneficial effects for the tiny niche of RC rocket glider enthusiasts. We get to ride on that wave of technology that makes what we do easier and economical, electronics wise.
 
George, what was your sample size on the Orange RXs? Typically, they tend to work well, with the occasional dud. I always range check them (all aspect, moving the model around to see if any position shadows the RX.) I have had zero failures with any Orange RXs that passed the power up and binding, plus the range check. The one dud I had would not bind.
I have had to reposition a couple of Orange RXs when the small antenna was shadowed by a lipo battery or by too many servo wires near the antenna in a FW positions.

Lots of threads discussing the Orange RXs over on RCG and the threads are quite positive. A few bad ones are reported, but only a few. I also have one of the very tiny 4ch Oranges in a 35mm EDF model and it has also worked well.

IIRC, they were 6-channel Oranges. The Stenbergs and myself were using those in various electric models, like Radians and F4F Wildcat. Every once in awhile, a crash when the plane quit responding.... but not that far away. Also happened to an electric sailplane I'd converted from a HL sailplane. It even happened on a test glide drop (carried up by a Radian) of a scaled up rudder-only Orbital Transport glider that had been fine in other flights, then spiraled in with no control but responded fine when we got to it. We finally realized, these problems NEVER happened when using Spektrum Rx's, only when using those Orange Rx's, so it wasn't a generic 2.4 spread spectrum thing. Quit using those 6 channel Orange Rx's, and have never had a radio-related problem that I can recall with Spektrum Rx's. Oh, just did recall a fly-away (landing in woods) with an A powered R/C R/G where the Ember "brick" stopped working, and the model was not quite as far away where it should have lost range yet. But nothing with a dedicated Spektrum Rx.

I do think the very tiny 4ch Orange Rx you mentioned may be the one I spoke of that worked OK, it has a limited range but the models used in it did not push that range. Well, not until D Superroc Alt at NARAM a year ago, the D2.3 powered model Ed LaCroix flew had tested out fine earlier, but on the contest flight the R/C ejection never went off (though it also had veered off badly and got DQ'ed before it crashed). But we knew those were pushing the range. if I ever get around to adding rudder only to a foam shuttle orbiter, I'll use that same Rx since for one it ought not to get far away, and for the other if it did spiral in it would probably not get much damage.

Anyway, another good reason to look into the Lemon Rx's is for possible use with small Multicopters. Several of the flight controller boards are now using one-wire or S-bus type inputs for all the servo channels via one signal wire instead of a bundle of wires with one signal wire per control channel. The only Spektrum Rx that supports that, IIRC, is big, heavy, and expensive. There is at least one small Lemon Rx that does that.

- George Gassaway
 
The Lemon 6ch RX does have a better antenna arrangement than the Orange. The Lemon has two wires for the single antenna, one coming off of each corner of the board on the side opposite the plug block, instead of the single wire antenna that the 6ch Orange has. Makes any signal shadowing less likely with the broader antenna span, plus you can orient one of the Lemon wires along the fuse and one 90 degrees to that, if desired.

Like I said, doing all aspect (top, bottom, both sides, front and back) range checks per Spektrum distance procedure did show a couple of Oranges with range issues from some aspects, but rearranging the RX in the aircraft has always cured it for me. Ditto with a couple of small actual Spektrum RX units.

Back from a trip to DC Thursday evening and hope to finish up the Popwing tomorrow.
 
Too much work to fly much.... Sigh.

The Popwing is ready to go once I get a good launch opportunity. Looks like the DARS launch for Saturday is going to be blown out, but we are talking about a local Black Friday launch, so that could be the next opportunity.

Need to update this build thread, for sure!

BTW, I am currently planning on making it to NARAM 58 this summer for the sport launch weekend, so we can have some RC fun up there....:)
 
Need to update this build thread.

The Mini Popwing is complete except for RX installation and adding launch lugs or rail buttons to it.

Not really enough of a fuse to use normal RCRG launcher.

My order of Lemon 2.4 Ghz micro DSMII RX units just arrived and one is going in the Mini Popwing. Just about made boost CG using a 2s 450 lipo buried in the front bottom surface of the wing, but will have to add a little bit of other weight as well.

I added a card stock fairing to the upper wing surface to sort of visually clean up the intersection of the motor tube and the foam wing.

There is an eighteen inch ruler in the picture for scale.

Hope to have a flight report very soon!

image.jpg
 
Back
Top