What is the "biggest" motor you launched an Estes Phoenix on?

I've flown mine on those. Also E15, E30, F12, F39.

Mine had (very small) epoxy fillets on the fins, a coupler inserted inside the rear BT and a bit of additional nose weight.

Anybody modify theirs for E9's?

I know, it's not AP... but you gotta like that 3 second burn - especially when you CHAD-stage a D12-0 to an E9-something.

I did an F39 and what a magnificent shred it was. I failed to meet structural stress requirements in the pre launch construction phase but it made it to about 100 feet and it was a very picture perfect vertical shredding. Well we live and learn.

I did it on a G55-10 or something like that... the rocket was reinforced with fiberglass and stuff and had fins replaced with plywood, and through the wall and all... that was the last time I ever saw the rocket again...

I think that would be too heavy. wRASP simulates my Phoenix (about 9.5 ounces) at 41.3 fps at 4 feet. D12 to E9 has a "V sub 4" of only 35 fps. On an 8 foot rod it gets to 42 fps which would probably be good enough for calm conditions. Provided that the rod does not significantly slow it down.

BTW, I weighed the parts of the kit right out of the bag. The tubes, coupler, nose, mmt tube, hook and half of the finstock, and the nose clay came in at over 8 ounces. I don't feel too bad about my 9.6 ounce bird.

We must be bewwy bewwy cawful...

The stock Estes Phoenix is right on the edge of stability. Flying it on a motor heavier than a D12 without compensating with some noseweight can be a problem. When we got the first samples of the Estes E9, we found out they were both underpowered and unstable.

As long as you add some nose weight to maintain the stock CG location, any of the mtors you mention should work. I know someone who HPR certified around the same time I did (1989) with a VERY beefed up Phoenix on an H motor.

The Phoenix is too heavy for an E9 and unstable. Adding nose weight to fix the stability problem is fatal to the liftoff, unless maybe you use a 10 foot rail!

The common mistake made with E9s is that people thik about the "E" part, and forget the "9" part. There are models that fly just fine on D12s that will NOT fly on an E9. The Phoenix is one of them.

phoenix will fly on a G or over, if you beef it up with fiberglass and stuff, BUT most likely it will fly so high that you will never see it again.

Sounds like a cool flight!

Ok, cover 1 eye and read this outloud......

E srtlen nitpo

; )

Randy

I checked for a CP location on Rocket Reviews and did not find one. I did a Barrowman calculation, splitting the top fins into two rectangles to better approximate what the BEq were expecting for inputs. I calculated the CP of the 30" rocket at 22.5" from the nose (7.5" from the tail). Anybody have numbers to confirm or contradict that?

I've flown the RMS D15's and E18's to some picturesque flights, even in some wind that made the RSO question the 24" chute for the pig. The F24 is a full case, so I figgered I would get the CP/CG relationship better known before I let it rip on that.

I'm not sure how much difference it makes, but the chute bucket keeps the chute and shock just below the nose. I guess every little bit helps.

I checked for a CP location on Rocket Reviews and did not find one. I did a Barrowman calculation, splitting the top fins into two rectangles to better approximate what the BEq were expecting for inputs. I calculated the CP of the 30" rocket at 22.5" from the nose (7.5" from the tail). Anybody have numbers to confirm or contradict that?

I've flown the RMS D15's and E18's to some picturesque flights, even in some wind that made the RSO question the 24" chute for the pig. The F24 is a full case, so I figgered I would get the CP/CG relationship better known before I let it rip on that.

I'm not sure how much difference it makes, but the chute bucket keeps the chute and shock just below the nose. I guess every little bit helps.

I've seen the maxi V-2 fly on E9's - a little slow off the rod, but very stable*

- and especially cool because of the slow liftoff. I think that as long as you launched in calm winds, an 'E' powered Phoenix would be fine, as it would weigh half (maybe a bit more than half) what a maxi V-2 does. I have a scratch-built BT-80 rocket that weighs a lot more than a Phoenix and it does fine on E9's.

• The V-2 / E9 combos that I have seen were launched from 4' or 5' rods.

I have seen E9-4 powered Estes phoenix missiles fly fine.

important facts:

• Nose weight is needed to make the CG move back to where it was with the D12-3 motor.

• This missile has fins above and below the CG, so if you do not line them up perfectly, they will act as "flaps" or "vanes" or "flap vanes" and generate lift that makes the rocket fly all over the sky (and maybe ground).

• With the correct nose weight, this will weight a few ounces LESS than a Maxi V-2 which can fly on an Estes E9-4. I strongly suggest using a 6 foot long 1/4" diameter steel rod to allow the model to build up airspeed.

If you fly it "normal" with a D12 it will go "x" feet high. If you add nose weight to fly it safely with an E9-4, it will go a tiny bit higher, but not as high as you might think AND every time you fly it with a D12-3 it will then fly lower than it would have in it's originally designed configuration. Somewhat of a waste.

-Fred Shecter

A couple of years ago I built an Estes Phoenix with a 29 mm MMT, Basswood fins that were TTW, and fiberglassed body. I balanced it as per the location noted on the plans. I have not flown it on anything but G33's and G64's. Recovery is a 18" nylon chute. Never have lost it because it's draggy and a bit weight laden so it does not go super high.

Changed the fins to birch ply, same thickness, and launch it on G64's all the time. Sounds extremely cool listening to the fins "sing" after the initial burn on it's way up.

-Booms

I had an LSO comment on the "Phoenix Whistle" one of the last times I launched it last year.

Tom K

Ya got me, Randy. Only thing that happened is my cube mate looked at me funny when I read it aloud so many times.

The Phoenix? Tom Allen and I made a few we called "Phast Pheonix." I launched mine on an I357 for a super blue flamer flight. I didn't judge the delay properly and got a bit of a zipper and also shredded the chute. The rocket had flashy silver fins and we saw it fall from about 3000 feet. Upon recovery, the only damage to be found was the 4 inch zipper. The G10 fins held up fine.

steve

; ) Ok, now cover the other eye and read it again.

Randy

weight to fly it

might think AND every

originally designed

Thoughtful analysis. It would behoove someone to run some predictions with Rocksim first, to determine if it's really worth modifying a Phoenix for E9's.

On a side note:

I have always suspected that the Phoenix's recessed motor mount reduced the motor's effective thrust (Krushnik effect), as well as creating more base drag than a flat-bottomed or boattailed design (obviously a boattail would ruin the scale properties though).

Has anyone here ever modified a Phoenix with a flush rear MMT, to see if the performance actually does increase enough to offset the extra noseweight needed?