Large Avro Arrow RC Rocket glider

[burkefj]

Decided to share here as well as FB in case anyone actually reads the glider topics, I am doing a kit of this that is 34" long with 2" tubing and 6mm depron wings, but I decided based on the CG and flight performance it might work as a 1.5x upscale using single ply 9mm depron, 3" tubing from Estes along with their lightweight cone, and just come in light enough to fly on the G-12 32mm reload, this will boost up to about 28 oz, this came in at 27.4 rtf with motor. Elevon control, 48" length, 37.5" wingspan, details added with sharpie pen, and hand cut vinyl for color except for the black on the nose. The roundels and lettering/numbers from stickershock. Intakes on the sides are just profile plates to give the look but be lightweight. It's about 1/17 scale, of course there are concssions to scale to make it work with the tubing/cone etc, but it looks the part.

Launches off a rail as per usual for me. Should boost to round 600', has a wing loading of 6.5 oz/sq foot after burnout which is pretty good at this size. Two servos, single 500mah 1s battery running them and the rx directly, very lightweight. CG shift covered by a glide trim setting only, no fancy balast adjustment. The cone came in at 2.4 oz after cutting off the base to allow mountng the battery, and only 2.5 oz was required for CG.

Frank

[frognbuff]

VERY cool! Love the Avro Arrow - would have been an awesome jet in operational service! Beautiful work!

[ghrocketman]

G12 ???
C'mon noww.
Try a G80 at LEAST.

[Fuse Eh!]

Wow, what can I say, that is an amazing version of our legendary (and too short lived) CF-105!! My Canuckian heart practically skipped a beat just reading the thread title; and the description details and picture brought me close to cardiac arrest. Wonderful job!

[tbzep]

Have you ever done a twin engine bird? It would add a little weight and complexity, but you need a little more challenge with your skill level!

The Avro reminds me of an F-5 Vigilante. I don't know why...maybe because of the single vertical stab when everything these days has two. The F-5 already has quite a bit of wing area, especially the reconnaissance version, so you wouldn't have to enlarge it too much to get a usable glide. It's not a delta, though.

Aviation buffs can tell me for sure, but I think the Vigilante had the first flying vertical stab (all moving like horizontal stabs that were already in use). I'm sure it used the same J-79's as the F-4 because those were the beasts of the late 50's and the Vigilante was a pretty good size plane.

[burkefj]

a "little weight" is an understement. In a tail mounted model like this for example, if you were to do two G-12's you add another 4.5 ounces in the tail which means at least 2.5 to 3 ounnces in the nose to balance, your CG shift will be even bigger now at burnout. Adding more than half a pound starts to kill glide, then you risk lighting two and not having one light....I like to keep it simple.

I've modeled the Vigilante before, I think the Arrow looks pretty close to the Rapier F-108 prototype which is also North American. For these bigger ones to fly in the G-12 long burn motor, weight is critical and it's a very fine line in cg placement, length, control placement etc to get it to work, a little mistake here and there and you add 4 ounces in a flash and then it's dead.

Frank

Have you ever done a twin engine bird? It would add a little weight and complexity, but you need a little more challenge with your skill level!

The Avro reminds me of an F-5 Vigilante. I don't know why...maybe because of the single vertical stab when everything these days has two. The F-5 already has quite a bit of wing area, especially the reconnaissance version, so you wouldn't have to enlarge it too much to get a usable glide. It's not a delta, though.

Aviation buffs can tell me for sure, but I think the Vigilante had the first flying vertical stab (all moving like horizontal stabs that were already in use). I'm sure it used the same J-79's as the F-4 because those were the beasts of the late 50's and the Vigilante was a pretty good size plane.

[burkefj]

Here is my other 150% upscale I just finished using the same tubing, slightly longer, also 9mm depron wings for G-12 and bigger wing still meeting the same weight of 27.5 oz rtf. It's an upscale of my Aurora Clipper kit I make for 24mm and which weighs 11 oz rtf. 150% gives 2.25x wing area so I'm a little over 2.2x in weight but reynolds helps as you get bigger.

[ghrocketman]

You need more kick than a G12.
Try at least a plugged G76G or how bout a G138T; thaty'll give you a real afterburner-power boost.

[ghrocketman]

In addition to the F-4 Phantom and A-5 Vigilante using two J79 engines, the F-104 used a single J-79.
That engine was also used in civilian applications as well, UNFORTUNATELY minus the afterburner.
FAR too few civilian aircraft have afterburners.

If I had unlimited $$$ resources I'd fly everywhere in a decommissioned F-4C/D or an F-16B/D. Those are occasionally available on the civilian market.
Gotta have a second seat for the passenger. The ejection seats and ABs would remain FULLY FUNCTIONAL too.
A F-5/T-38 would be far more economical, but they have ZERO on-board ground starting ability; they have to start by an external APU, making practical use impossible.

[burkefj]

Clearly you don't understand the concept of "the speed of foam" :) In addition in reality long burn with large wings gives more altitude as drag at high boost speeds with a large wing is rediculous. Plus these are large and light which means their mass doesn't carry them far in coast even if you get the higher speed.

Boost speed and flutter are a real problem, G-25 reload might be ok, but it's an ounce heavier, so my overall weight would be about 1.6 ounces heavier, cg shift might be ok. the longburn G-12 single use Gary has been trying to get certified would be perfect, still same boost speed but an extra 4 seconds of burntime.

Here is a similar sized X-15 I did boosting on a G-40, however it weighed an extra 11 ounces more and even so this was a pretty fast boost speed if you are trying to control it.

https://youtu.be/grpnfTewUmw

Second is what happens in a large model when you mix light weight and a G-40 with too long a wingspan..

https://youtu.be/mOhngbhZDWI

The killers of tail mounted rocket gliders are tail weight and CG shift, so just sticking a bigger motor is not the answer in almost every case.

You need more kick than a G12.
Try at least a plugged G76G or how bout a G138T; thaty'll give you a real afterburner-power boost.

[tbzep]

a "little weight" is an understement. In a tail mounted model like this for example, if you were to do two G-12's
Two G-12's would get you 186 Ns total impulse, putting it into HPR rules anyway, if that's an issue at your field.

I understand what you're saying. I was thinking about smaller motors, which still would add weight over the single larger motor, but I haven't actually looked at the potential motor selection before now. You don't have anything that, flown in pairs would come close to meeting similar weight and thrust profile as a single G-12.

Apogee/Aerotech has a couple motors that are long burn, but their casings are similar in size to the G12 (the F13 uses the same casing) and would be about as heavy as a pair G-12's. To make it feasible they'd have to be nearly half the weight, and as a pair provide a good enough thrust profile to work with.

[burkefj]

Yup, if Aerotech can get the G-12 single use 29 to meet temp or change the temp rules, that would give a 140 or more ns G motor with a 12 second burn, I've flown two and they were great in a model this size for only 1 ounce more tail weight.

Two G-12's would get you 186 Ns total impulse, putting it into HPR rules anyway, if that's an issue at your field.

I understand what you're saying. I was thinking about smaller motors, which still would add weight over the single larger motor, but I haven't actually looked at the potential motor selection before now. You don't have anything that, flown in pairs would come close to meeting similar weight and thrust profile as a single G-12.

Apogee/Aerotech has a couple motors that are long burn, but their casings are similar in size to the G12 (the F13 uses the same casing) and would be about as heavy as a pair G-12's. To make it feasible they'd have to be nearly half the weight, and as a pair provide a good enough thrust profile to work with.

[LeeR]

Clearly you don't understand the concept of "the speed of foam" :)

Funny!

When I was about 13, I put a B14 in a Flying Jenny, a biplane boost glider free plan from Estes. As an adult I described that short flight as “exceeding the speed of balsa”.

I obviously did not understand thrust curves, or motor designation meanings.

[tbzep]

Gotta have a second seat for the passenger. The ejection seats and ABs would remain FULLY FUNCTIONAL too.
Heck yeah. Passenger blabbing too much? No problem. Eject eject eject!

[burkefj]

Here's the fight video from Friday the maiden flight and second flight

https://youtu.be/tv4pCCWAyYo