Aerotech Phoenix new build

The Rocketry Forum

Help Support The Rocketry Forum:

eshenderson

President CATO
TRF Sponsor
Joined
Nov 10, 2011
Messages
105
Reaction score
92
After watching the amazing flight at the last URRF up in Potter, I had to get one. I recently bought one on ebay and am now looking at the build.

Currently, the bulk of the construction materials are balsa. With the new lighter weight materials available on the market, why wouldn't I replace the balsa air frame with carbon fiber angle iron and .005 G10? Also, is there any reason that I would not replace the balsa skin on the foam core wings with carbon fiber tissue and vacuum them? Seems that i would end up with a lighter bird that would take more abuse.

Any feedback would be appreciated.
 

tab28682

Well-Known Member
TRF Supporter
Joined
Jul 30, 2014
Messages
1,853
Reaction score
437
I would be hesitant to change what Bob Parks did.

The Phoenix is amazingly strong and light for its size.

The airfoil is already designed with the wing skin thickness accounted for. You might be able to save a tiny bit of weight if you vacuum bagged the wings and skinned the with glass and a little strategically applied carbon laid up on Mylar sheets, (Ala current composite sailplane practice) but the airfoil thickness would be off a little.

While the carbon fiber extruded shape structure skinned with very thin G10 might sound like a good idea, keeping the weight down to anything comparable to the stock balsa fuse would be extremely difficult and basically impossible.

My suggestion would be to build it exactly like Bob Parks says to do it. His engineering acumen is beyond reproach. You could make templates of some of the shapes and then try to build another one using different materials and see how it comes out.

Bob Parks hangs out and posts occasionally over on RC groups. If you are really set on doing something mdifferent with the model, I would discuss it with him, first.

My Phoenix kit is on my eventual build list...:)
 
Last edited:

KevinM

Well-Known Member
Joined
Sep 4, 2009
Messages
127
Reaction score
36
I'm a Phoenix builder/driver, and while I'd also recommend generally not straying from Bob's build, there is one tweak I will recommend. The Phoenix was designed to work with much heavier radio gear than what we have available today, when I built mine I had to place a very large Rx battery pack (4 cell, 1100 mAh NiMh) in the nose to get it to balance. One thing you might consider doing to enable you to better take advantage of lighter equipment is to increase the wing sweepback by an inch or two from the plan design and recalculate the required CG for the new planform accordingly.

Phoenix_on_pad.jpg

go.jpg

Good luck on your build, and have fun - it's an awesome bird!
 

tab28682

Well-Known Member
TRF Supporter
Joined
Jul 30, 2014
Messages
1,853
Reaction score
437
I'm a Phoenix builder/driver, and while I'd also recommend generally not straying from Bob's build, there is one tweak I will recommend. The Phoenix was designed to work with much heavier radio gear than what we have available today, when I built mine I had to place a very large Rx battery pack (4 cell, 1100 mAh NiMh) in the nose to get it to balance. One thing you might consider doing to enable you to better take advantage of lighter equipment is to increase the wing sweepback by an inch or two from the plan design and recalculate the required CG for the new planform accordingly.

View attachment 303801

View attachment 303802

Good luck on your build, and have fun - it's an awesome bird!
An excellent idea. A reasonable change that makes the model easier to use with modern radio gear.
 

georgegassaway

Lifetime Supporter
TRF Lifetime Supporter
Joined
Jan 18, 2009
Messages
4,791
Reaction score
715
Another factor against going from balsa wing skins to composite, besides the thickness of the balsa as Tom noted, is that the foam cores are low density "white foam". If you want to to with a composite wing using fiberglass/graphite skins, the white foam would be too fragile.

Also BTW, white foam cores like those are meant to be bagged at around 5 to 7" hg of vacuum. If you used a strong vacuum as usually used for fiberglass/graphite or other composite layups, like 15 to 20", you will CRUSH the white foam. I onetime accidentally bagged a left wing of a white core at about 10" vacuum, and that wing's core was permanently compressed, it ended up about 1/16" thinner at the root than the right wing (7/16" vs 1/2"). The model was flyable but not vey good. And the left wing stalled before the right wing did.

So, if you do the original white core wing with balsa skins, be careful not to set the vacuum level too high or the white foam will crush.

If you really truly wanted to do a composite wing, then you'd need to get new cores cut, for the correct airfoil thickness and using blue foam of some other stiffer foam ("Spyderfoam" is the best but a bit pricey). I get cores cut by "Flying Foam".

But I really think the model is better off with the original balsa and white foam core method. I will say that since I like slower boosting gliders, that if i was building a Phoenix, I'd replace the medium to heavy-ish balsa skins in the kit with the lightest balsa I could get, and boost on G12 power. I would add a bit of glass cloth under the skin near the center section and perhaps a thin graphite strip mostly spanwise under the skin as a "spar". I do not recall for sure if the Phoenix kit used some 3/4" or whatever width of fiberglass tape between skin and core as a sort of spar.

I do know that the regular model was designed to hold up to a lot of power, IIRC has flown and held up to G40 power. But anything beyond that might shred it. I don't like crazy-fast boosts though, and the model has to be built so heavy to take such a boost velocity that I'd rather go up slower on boost and have a much lighter model for the glide.

Also, if I built a Phoenix, I do not think I'd bother with the rudder, just to save weight. Even though I mainly fly 2-channel models with rudder-elevator (or 3 ch with throttle) and do not fly aileron models much. The good thing is that the Phoenix has some dihedral and handles nicely with ailerons. I've never owned one, but got to be the test pilot for a couple of newly built models that some college students were using for a rocket oriented "Ultimate Egg Drop" competition. The dihedral (plus sweepback dihedral effect) made them easier to fly than I had expected since I had very little aileron model experience at the time (enough not to be a danger, but not enough to feel very confident. But in a not-ideal situation that was the best option).

FWIW - here’s a page on what I did to modify an old Vector Aero “Cuda” rocket glider to use a center flap to try to land more accurately. I also totally revised the fuselage layout. But that it not the point it is to explain why it’s so different.

The point is how, if you used lighter balsa for the skins, you could do a thin graphite “spar strip” under the skins, as well as some fiberglass cloth as needed. for this one I had to add some fiberglass cloth to make of for the loss of structural integrity with the cut-out flap.

Also one of my biggest tips for spreading epoxy for an even thin amount is to use a bit of dye pigment, I used pigment powder, to make the epoxy red. So when I squeeged the epoxy out into a thin “sheen” of epoxy, the wood had a light pinkish appearance. Any areas with too much epoxy looked darker, in more need of squeegeeing to remove the excess. This also made sure there were no missed areas. Very hard to tell that when the epoxy is clear and not dyed. FWIW, anyway. I do not do that dye pigment with composite wing layups though, other than for the leading edges.

https://georgesrockets.com/GRP/GLIDERS/CUDA/CudaFlap.htm

 
Last edited:

MaxQ

Tripoli 2747
Joined
Jan 18, 2009
Messages
4,453
Reaction score
84
Location
Central Viginia - USA
I love my Aerotech Phoenix.
I built it box stock.

After a few flights I noticed I had a stripped elevator servo gear.
The rudder and elevator square stick balsa pushrods are a tight fit inside the tail boom.
One was rubbing against the other...I replaced one with narrower hard dowel.

I also put tri-stock strip at the base of the vertical fin to reinforce it.
 
Last edited:

JoeG

Well-Known Member
Joined
Apr 9, 2009
Messages
773
Reaction score
37
After watching the amazing flight at the last URRF up in Potter, I had to get one. I recently bought one on ebay and am now looking at the build.

Currently, the bulk of the construction materials are balsa. With the new lighter weight materials available on the market, why wouldn't I replace the balsa air frame with carbon fiber angle iron and .005 G10? Also, is there any reason that I would not replace the balsa skin on the foam core wings with carbon fiber tissue and vacuum them? Seems that i would end up with a lighter bird that would take more abuse.

Any feedback would be appreciated.
Congratulations on getting a kit. I would think they would be getting harder to come by unless everyone is just buying and selling the same one over and over. Maybe they are like they say about fruit cakes. There really is just one Phoenix glider kit that keeps getting sold and bought. I know that's not true because I am looking at my unopened kit in the corner as I type this.

I have built a few of these over the years and it was I that flew the "Super Phoenix" at Potter this year.

I have changed things over the years and always end up coming back to the original construction materials and techniques. The Phoenix is pretty strong, as has already been noted. I haver flown mine on G25's but I like the G12's the best and a stock Phoenix will hover in a 10MPH wind so you don't want to make it too light so it doesn't penetrate the wind. I don't know about you but most launches I go to are usually in the 5 to 15MPH range and so you need a little weight to get back to the pad.

One thing I do change is to trade out the push rods for smaller diameter fiber carbon tubes. These are less flexible than the balsa sticks and take up a lot less room.

The Super Phoenix (2 times upscale of the original) does not have a rudder but a one piece vertical fin. It was done that way for expediency when my son and I rebuilt it after a pretty major catastrophe during LDRS XXXI. It flies fine that way and unless you are planning on a fully precision aerobatic machine with stall turns and four point rolls it flies just fine with no movable rudder. Loops and rolls are easily done without it. You also save the weight (and cost) of the extra servo and pushrod.

Good luck on your project and keep us informed about your progress. I expect to see it at Potter this Spring.
 

eshenderson

President CATO
TRF Sponsor
Joined
Nov 10, 2011
Messages
105
Reaction score
92
Thanks to all for your input. As I / We are novices at RC planes of any form, we were looking to make this thing as bullet proof as possible. The lighter / stronger components available today as compared to 1991 seemed like the way to go as we were also looking to add a FPV camera in the nose and figured that would add additional weight. Some of this added weight can be compensated for by the lighter weight receivers and servos available today, but we figured we could reduce the weight of the air fame and make adjustments to keep the CP where it needs to be.

I envision catching a stray onion up in Potter trying to land the thing and watching it cartwheel into a million balsa toothpicks.......

Guess we will build it as is (with the carbon push rods) and then try modifications on subsequent builds. I am still leaning toward adding Kevlar Tissue to the wings as the additional weight is minimal and the wings should be 50% stronger.
 

BBrown

Kloudbuster Prefect
Joined
Dec 9, 2009
Messages
474
Reaction score
283
Location
Wichita, KS
Congratulations on getting a kit. I would think they would be getting harder to come by unless everyone is just buying and selling the same one over and over. Maybe they are like they say about fruit cakes. There really is just one Phoenix glider kit that keeps getting sold and bought.
Joe,
If there is any truth to your statement, I'm the current holder of "the kit"! I picked one up at AirFest and plan to build it stock with CF pushrods. One of the regulars down on the rocket pasture has one and has flown it several times. We are kind of hoping to fly them at the same time this coming spring.
Bob
 

mikec

Well-Known Member
Joined
May 9, 2009
Messages
2,541
Reaction score
397
As I / We are novices at RC planes of any form...
Please don't let the Phoenix be your first R/C experience. Buy a cheap electric plane and get a lot of experience first. Otherwise you will crash pretty much guaranteed and it won't matter how strong the Phoenix is.
 

tab28682

Well-Known Member
TRF Supporter
Joined
Jul 30, 2014
Messages
1,853
Reaction score
437
Please don't let the Phoenix be your first R/C experience. Buy a cheap electric plane and get a lot of experience first. Otherwise you will crash pretty much guaranteed and it won't matter how strong the Phoenix is.
Let me strongly second this advice. The Phoenix is REALLY not a suitable model for a novice RCer. Get a good RC simulator for your computer and practice a bunch. Then, do lots of practicing with an electric trainer and some sort of follow on more advanced model. I would not try to fly the Phoenix until you are very comfortable with a low wing acrobatic RC aircraft.

I know of more than one rocket person that built and attempted to fly a Phoenix with little or no RC experience. None of them survived the first flight with major damage or a total crash.
 
Last edited:

dhbarr

Amateur Professional
Joined
Jan 30, 2016
Messages
7,351
Reaction score
1,773
Let me strongly second this advice. The Phoenix is REALLY not a suitable model for a novice RCer. Get a good RC simulator for your computer and practice a bunch. Then, do lots of practicing with an electric trainer and some sort of follow on more advanced model. I would not try to fly the Phoenix until you are very comfortable with a low wing acrobatic RC aircraft.

I know of more than one rocket person that built and attempted to fly a Phoenix with little or no RC experience. None of them survived the first flight with major damage or a total crash.
Is RealFlight / Interlink / Futaba still the way to start?
 

JoeG

Well-Known Member
Joined
Apr 9, 2009
Messages
773
Reaction score
37
Joe,
If there is any truth to your statement, I'm the current holder of "the kit"! I picked one up at AirFest and plan to build it stock with CF pushrods. One of the regulars down on the rocket pasture has one and has flown it several times. We are kind of hoping to fly them at the same time this coming spring.
Bob
Bob,

Well, it seems you have certainly debunked my theory. There must have been a bunch of these that were sold but never got built. Wish I was closer. How about three of them at once? A Phoenix drag race? Spot landing? Longest glide?
 

JoeG

Well-Known Member
Joined
Apr 9, 2009
Messages
773
Reaction score
37
I too would not recommend flying this with no experience. Simulator time is very valuable and cheap and fun. The RealFlight simulator will cost you less than you probably paid for the kit and considering that you will need to buy a new kit (trust me on this) if you don't have some experience it is money well spent. It is not difficult to fly R/C but you need to learn how. Over controlling and losing orientation are two big problems. Understanding that ailerons and rudder are reversed when the plane is flying toward you is easy. Learning to respond correctly is not easy nor automatic. I have had to wrestle the transmitter away from a few folks I have helped learn to fly because they KNEW they were providing the correct input when it was exactly the opposite.

You really are getting good advice here from everyone.
 

tab28682

Well-Known Member
TRF Supporter
Joined
Jul 30, 2014
Messages
1,853
Reaction score
437
Is RealFlight / Interlink / Futaba still the way to start?

Realflight is an excellent RC flight sim and one of the most popular. Futaba is fine but there are other ways to go. I personally like Spektrum.
 

BBrown

Kloudbuster Prefect
Joined
Dec 9, 2009
Messages
474
Reaction score
283
Location
Wichita, KS
Bob,

Well, it seems you have certainly debunked my theory. There must have been a bunch of these that were sold but never got built. Wish I was closer. How about three of them at once? A Phoenix drag race? Spot landing? Longest glide?
Wouldn't that be cool! I wonder how many kits were produced back in the day?
 

georgegassaway

Lifetime Supporter
TRF Lifetime Supporter
Joined
Jan 18, 2009
Messages
4,791
Reaction score
715
Oh, yeah, absolutely you need to learn how to fly R/C first!

Preferably on a computer simulator, and then on SOME sort of real model, even if it's a $$50 "toy-ish" model. Or a closer to $100 "real" R/C plane, typically out of foam which can take a lot of crashing with little damage. Given the cost-per-flight of a Phoenix, that's not much to spend to learn to fly properly. And this is not counting the cost of the Phoenix, building it, the radio gear, and the pad/tower that it needs. So a lot of investment to not learn to fly properly, which could result in total destruction on flight #1.

BTW - there was a RealFlight file for the Phoenix. I do not recall if it is still available on the web anywhere. But I might be able to get hold of it if you are interested (It's a free file, no copyright issues AFAIK). The boost is a bit flaky but if you can handle the boost in the simulator, then the real thing is easier. Glide-wise it glided nicely in the sim. One of the most fun ways to to fly it in the sim was to set up to fly from a slope site, with about 10-15mph wind up the slope face, and slope-soar it back and forth for many minutes.

Whatever you do, please use an F13 or G12 for the first few flights (F13 has the same thrust curve as the 8 seocnd burn G12, but burns out after 3.5 seconds, so the F13 is great for flight #1). The slow liftoff of the F13/G12 will be easier to control the boost and get used to it. The higher the thrust, the harder it gets. Don't do something crazy like a G80, even if the wing could take it.

On these models, lower weight is your friend (as long as the CG is correct, if it needs noseweight, then you gotta add noseweight. But try to locate as much of the R/C gear as far forward as practical). Building "over-strong" in general is your enemy (other than suitable strengthening of localized weak spots). Over-strong building adds weight that hurts the boost altitude, degrades glide, and makes hard landings/crashes just over-stress some other parts more.

FWIW - some previous TRF threads on R/C RBG's, the first one related to the Phoenix:

https://www.rocketryforum.com/showthread.php?58980-New-To-RCRG

https://www.rocketryforum.com/showthread.php?122109-RC-glider-beginner-tips

https://www.rocketryforum.com/showthread.php?41050-Learning-R-C

- George Gassaway
 
Last edited:

jsargevt

Well-Known Member
Joined
Jun 18, 2011
Messages
1,541
Reaction score
7
Ah another Phoenix dreamer! I, too have a Phoenix kit and have been getting up the nerve to build it. I started in the same place as you without ANY RC experience. I will echo what everyone else says and recommend getting some time on a trainer and a real plane before flying the phoenix.

I picked up an electric foam glider to learn how to fly on. It is extremely forgiving and they are pretty inexpensive. I picked up a Flyzone Calypso and it is a good plane. I strongly recommend finding a RC group to fly with. Most of them are extremely welcoming of new people and will likely get you started on a trainer with a buddy box so you can practice without risking your plane. I can also recommend the Horizon Hobby Whip-It hand launch glider for practice as well. That is a hoot in a small field and it flies EXTREMELY well. If you get bored of it it can be turned into a RC boost glider pretty easily as well by inverting the wing and attaching a boost pod. Someone around here has done that....I just don't know who.

As far as RC gear goes, all of it is pretty amazing. Find out what flavor is favored at your RC site and that will likely be a good choice. That way someone can help you figure out how to use the radio as they can be complex.

Realflight is a great learning tool. There is a Phoenix RF file out there - you might have to look but its there.

Good luck! Maybe this will be the building season that I assemble the Phoenix!

If anyone is interested in a Phoenix I do have a second kit stashed away. I am reluctant to part with it, but send me a PM and we can discuss.
 
Last edited:

soopirV

Well-Known Member
Joined
Sep 1, 2010
Messages
1,157
Reaction score
6
I had never heard of this kit, and got excited when I saw this post, thinking that AT had FINALLY released a new kit! Any one know what's up with them? Haven't seen anything new in close to a decade I think?
 

tab28682

Well-Known Member
TRF Supporter
Joined
Jul 30, 2014
Messages
1,853
Reaction score
437
I had never heard of this kit, and got excited when I saw this post, thinking that AT had FINALLY released a new kit! Any one know what's up with them? Haven't seen anything new in close to a decade I think?
The Phoenix can still be had once in a while here in the for sale forum and on EBay.
 

MaxQ

Tripoli 2747
Joined
Jan 18, 2009
Messages
4,453
Reaction score
84
Location
Central Viginia - USA
I had never heard of this kit, and got excited when I saw this post, thinking that AT had FINALLY released a new kit! Any one know what's up with them? Haven't seen anything new in close to a decade I think?
As Mike posted , this OOP kit by Aerotech had brief reissue run by Sky King, so if you do a search you might search for both the Aerotech and Sky King Phoenix productions.
IIRC the Sky King version had CF pushrods and laser cut parts which were nice improvements.

https://www.rocketryforum.com/showthread.php?28110-Aerotech-SkyKing-Phoenix-RCRG




I believe I found mine (original Aerotech release) on RC Groups....was a bit labor intensive but built into a beautiful flying RG that looks pretty darn cool on the pad, always gets comments at a launch.
 
Last edited:

fyrwrxz

latest photo
Joined
Jun 6, 2011
Messages
6,619
Reaction score
93
These are getting really hard to find, esp. since Ed discontinued the SkyKing version. If anyone seriously wants an original Aerotech version, pm me. And yes, I'm emotionally attached. Not cheap, but I'm not making a profit either. It's what I paid. Too many other rocket projects.
 

eshenderson

President CATO
TRF Sponsor
Joined
Nov 10, 2011
Messages
105
Reaction score
92
In for a penny, In for a pound. I just cleaned Balsa Machining out of their inventory of F13 and G12 reloads. Must be the optimist in me that the Phoenix will survive the first flight. As I have a limited number of potential launches (based on motors, not flying skill) what are others doing to modify the kit to accept something other than the 32mm reloads?
 

burkefj

Well-Known Member
TRF Supporter
Joined
Jan 27, 2009
Messages
3,442
Reaction score
1,001
You can make a simple cardboard sleeve out of slit 29mm tube to adapt any 29mm motor to fit and then just stay within reasonable flight speeds/stresses.
That's what I do on my larger rc rg's that were built with 32mm tubing...the regressive G25 may be ok, however it is much longer than a G-12...



Frank
 

Initiator001

Well-Known Member
Joined
Jan 19, 2009
Messages
2,934
Reaction score
214
Wouldn't that be cool! I wonder how many kits were produced back in the day?
I recall the initial production run was around 1,000 units.

The Phoenix was a first-class, quality product but like other R/C rocket gliders produced by other companies it didn't catch on.
Darned exciting to watch fly in the hands of an experienced pilot.
 

jsargevt

Well-Known Member
Joined
Jun 18, 2011
Messages
1,541
Reaction score
7
FYI to all: Sky King closed shop last year (maybe the year before?). They discontinued the Phoenix long ago but they had some great slopers for sale that are now gone.

I always thought that the new CTI Mellow Yellow in 29mm would make a good RC motor. You can also order the motors (and case) direct from AT. The list price on that case is insanity.....
 

James Duffy

Well-Known Member
Joined
Jan 19, 2009
Messages
1,061
Reaction score
552
The Phoenix was a first-class, quality product but like other R/C rocket gliders produced by other companies it didn't catch on.
This raises an intriguing point for discussion: what would it take for a R/C rocket glider to become a successful product? Why have previous attempts to establish this market failed?

I have my own thoughts on the subject but would really like to hear what others have to say.

James
 

ttabbal

Well-Known Member
Joined
Jan 19, 2009
Messages
1,083
Reaction score
23
I this there are a couple of things that hold people back from them.

They require RC flying skills and equipment. Not a lot of people have them. With drones getting more popular and with RC gear prices down, these are less of an issue than in the past. Perhaps offering a kit with some cheaper gear would help. Or directing people to them at least. You don't need a nice Spektrum or Futaba for this stuff, the $30 Orange Transmitter is sufficient. If you like it, there are advantages to the nicer gear, but people see RC and think they need to drop $300 on the TX. Learning to fly does take some time though. Perhaps using one of stabilized receivers could help somewhat. I know Orange, flysky and frsky have reasonably priced options now.

The AT RC case is stupid expensive. I get that it's a low volume part but it still seems excessive to new users, and some older ones. I'm not sure what to suggest though. Maybe some single use long burn motors? Maybe something similar for cheaper cases? Perhaps designs that can fly well on the AT F12 load for the 24mm hobby case? That's not as nice for RCBG as the E6-RC, but the hardware is far cheaper and can be used for Estes rockets etc.. A moon or end-burner for the 24/60 might work well...

They tend to require tower launchers etc.. Not many clubs have equipment for that, and people don't want to buy special gear for something that they might not want to get really into. Some of the designs and kits burkefj has help here as they can use standard rod and rail launchers.
 
Top