29mm motor upgrades without ttw fins?

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AtomicStorm

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I have a few lpr builds coming up that i plan on upgrading from 24mm to 29mm. The olympus, the vapor and the camanchee 3(not sure about 29mm yet on c3, but maaaaaaybe lol). I usually use tightbond 3 for the first fillet then i come back with tightbond thick and do a couple more layers of fillets producing a really good looking fillet that i "think" may be strong enough without ttw fins. So is tightbond strong enough or do i need to switch to 30 min epoxy? Also is it really necessary for ttw fins with 29mm?
 

Art Upton

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LOC's original AURA rocket was fins glued to the Body tube but using the Kraft Tube "Rivets" method of putting pin holes into the body tube on the fin root part of the glue joint. First time I saw this was in the 70s on FSI rockets... The 38mm diameter LOC AURA rocket was flown on 29mm motors.... in the age before trackers it was a 50/50 chance of fire and not be seen again , Hi HI
 

mtnmanak

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I have a few lpr builds coming up that i plan on upgrading from 24mm to 29mm. The olympus, the vapor and the camanchee 3(not sure about 29mm yet on c3, but maaaaaaybe lol). I usually use tightbond 3 for the first fillet then i come back with tightbond thick and do a couple more layers of fillets producing a really good looking fillet that i "think" may be strong enough without ttw fins. So is tightbond strong enough or do i need to switch to 30 min epoxy? Also is it really necessary for ttw fins with 29mm?
I have flown 29mm minimum diameter rockets at above Mach 1 with surface mounted fins. You should be fine with Tightbond if you are only flying low/mid power motors. If you want better strength, glass the fins tip-to-tip. Easy to do and a good technique to have in your "build arsenal". They won't come off no matter how hard you fly it. You do need epoxy for that, though.
 

AtomicStorm

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So the last time i did ttw fins was on the estes crossfire little guy and whenever i went to glue the fillets, the bt started to warp and it turned out not looking so well. Does it just do that with wood glue because of the moisture or what? Sry for the noobness lol
 

AtomicStorm

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I have flown 29mm minimum diameter rockets at above Mach 1 with surface mounted fins. You should be fine with Tightbond if you are only flying low/mid power motors. If you want better strength, glass the fins tip-to-tip. Easy to do and a good technique to have in your "build arsenal". They won't come off no matter how hard you fly it. You do need epoxy for that, though.
I thought about doing fiberglass but it seems like a mess and alot of weight for a lpr. I do however paper the balsa fins with tightbond and give them a nice airfoil shape on the leading edge as well as thinning out the aft edge for drag reduction and the lift effect so that should help alot.
 

mtnmanak

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So the last time i did ttw fins was on the estes crossfire little guy and whenever i went to glue the fillets, the bt started to warp and it turned out not looking so well. Does it just do that with wood glue because of the moisture or what? Sry for the noobness lol
Yes, that is the moisture in the glue combined with a very lightweight cardboard tube with nothing to back it up.

For TTW fins on a cardboard rocket, you can try a technique common on high power builds. When you insert the MMT, don't glue the rear centering ring on. Leave it loose and at the end of the MMT - only glue the front ring onto the MMT and into the airframe and leave the rear ring sticking out about half way. Once the glue dries on the front ring, pull the rear ring out. Then, glue your fins' root edges to the MMT. Once dry, use a stick to paint in some internal fillets against the body tube and fin. Then glue your rear centering ring in and push it against the fins. This provides very stable/secure fins. After that, the outer fillet is more or less cosmetic.
 

heada

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When you paper the fins, paper them tip to tip. It's the LPR version of fiberglass tip to tip. Perfectly strong for pretty much any G motor or below.
 

AtomicStorm

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I have flown 29mm minimum diameter rockets at above Mach 1 with surface mounted fins. You should be fine with Tightbond if you are only flying low/mid power motors. If you want better strength, glass the fins tip-to-tip. Easy to do and a good technique to have in your "build arsenal". They won't come off no matter how hard you fly it. You do need epoxy for that, though.
So do you think that tightbond on 400grit lightly sanded bt is stronger then apoxy? I really like the work time and how the tightbond sands. I can always get a professional looking thick fillet and then i skin then fins with computer paper and bring the lip of the paper over the fillet maybe a few cm on to the bt, i thought that might add a little more support. Heres a pic of the fillets from my latest "mean machine" build.
 

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mtnmanak

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So do you think that tightbond on 400grit lightly sanded bt is stronger then apoxy? I really like the work time and how the tightbond sands. I can always get a professional looking thick fillet and then i skin then fins with computer paper and bring the lip of the paper over the fillet maybe a few cm on to the bt, i thought that might add a little more support. Heres a pic of the fillets from my latest "mean machine" build.
Very nice looking - great job!

As I have noted on TRF before, giving advice about glue/epoxy is like giving advice about religion and politics ;)

Having said that, for wood and cardboard, I think nothing beats Tightbond. In my opinion, it is better choice than epoxy for most wood/cardboard joints for LPR/MPR. If you move up to HPR, there comes a point when epoxy is the better choice, but at 29mm LPR/MPR, Tightbond is perfect.

Normally, I would not say anything about fiberglass tubes for LPR/MPR, but they are becoming more popular. Mach 1 even has some FG kits that fly on Estes 18mm motors, so throwing the FG caveat is necessary - if you use FG anything, Tightbond will not work. You need epoxy.
 

AtomicStorm

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Tightbond it is then or i may do tightbond fins on one and epoxy fins on the other and see which one fails first.
 

heada

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Wood glue and epoxy both form bonds that are stronger than the base wood/paper material. I use wood glue in wood/paper materials due to weight savings.
 

SharkWhisperer

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LOC's original AURA rocket was fins glued to the Body tube but using the Kraft Tube "Rivets" method of putting pin holes into the body tube on the fin root part of the glue joint. First time I saw this was in the 70s on FSI rockets... The 38mm diameter LOC AURA rocket was flown on 29mm motors.... in the age before trackers it was a 50/50 chance of fire and not be seen again , Hi HI
I frequently use pin holes with surface-mounted LPR/MPR. Through the body tube in a staggered line about 2 mm apart, and also into the root edge of the fins if balsa (difficult to poke pinholes in basswood or plywood). I use Tightbond II to attach wood to cardboard. After it dries, you'll be able to feel lines of hard tiny beads on the inside of the body tube that might need sanding down smooth to fit motormounts (or motors if it's friction fit to the BT).

With good filets, it seems to add another measure of durability and I've never noticed it to compromise the BT integrity/strength. Occasionally, I've taken a small paintbrush and painted a thin layer of CA over the bead line inside the tube just to toughen up the wall in the vicinity of the Tightbond-filled holes, but that's probably just unnecessary insurance. Trivial extra weight for the satisfaction of a little extra peace of mind...
 

bill_s

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29mm version of the Vapor is the Star Orbiter
Not exactly, but the Star is essentially their regular rocket modified for 29 mm motors, or really intended primarily for the 29 mm BP motors.

I flew my unmodded Vapor recently on an F44, OMG. For a rocket that doesn't have to be launched from a great distance, soooo fast. I built it because I killed my 24 mm rocket (drag seperation! unusual design) and had motors left over. I don't see building a kit if it's not what you want, although it would be easy to upgrade --- as is, it very light and flies well on 24 mm BP motors. I was disappointed at first by the surface mount fins, but they have 7.5" of bonding area each, that's the way to do it.

Since the centering rings are cardboard, I added a longitudinal reinforcement, also cardboard, to compensate some for lack of the TTW support.
 

Back_at_it

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You will be fine with surface mount fins. I prefer epoxy but honestly, Titebond 2 will work fine with thick and quick for the fillets. I built and have flown my upscale Bullet on 29mm several times and it has surface mounted fins.

The only recommendation I have for you is to sand the body tube where the fins and fillets will attach and consider replacing the fins with basswood. Depending on the body tube size, you might also consider replacing at least the upper centering ring with plywood. I've had more issues with paper centering rings fail than fins so I now use plywood in anything large then BT55.

bullet rocket.jpg
 

heada

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Not exactly, but the Star is essentially their regular rocket modified for 29 mm motors, or really intended primarily for the 29 mm BP motors.

I flew my unmodded Vapor recently on an F44, OMG. For a rocket that doesn't have to be launched from a great distance, soooo fast. I built it because I killed my 24 mm rocket (drag seperation! unusual design) and had motors left over. I don't see building a kit if it's not what you want, although it would be easy to upgrade --- as is, it very light and flies well on 24 mm BP motors. I was disappointed at first by the surface mount fins, but they have 7.5" of bonding area each, that's the way to do it.

Since the centering rings are cardboard, I added a longitudinal reinforcement, also cardboard, to compensate some for lack of the TTW support.
Star Orbiter came first and is designed for 29mm from the beginning. The Vapor is a Hobby Lobby exclusive and uses nearly all the same parts except for 24mm and different fin shape. You can get a Star Orbiter for $15 from ACSupply so nearly the same cost as the Vapor.


When comparing them, the Star Orbiter is the better rocket. It is slightly longer and so more stable, it has TTW fins standard and will fly on anything from BP E16 motors to APCP G motors without modification and beyond if you tweak it slightly. I have flown a Star Orbiter on a G54 that also had a Eggtimer Quark in an Apogee av-bay to make it dual-deploy. If you think the F44 was impressive, pop a big G in the Star and have your socks blown off. You could upgrade the rings to lite-ply and put an H180 in it and go supersonic and over a mile high if you wanted.
 

Jmhepworth

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The Apogee Aspire is 29mm min diameter with surface mount balsa on cardboard. Many of us have built them with wood glue and the fins only pop off when they hit the ground. Whether the fins stay on depends more on build technique than the type of glue. Papering the fins can help if you plan to use a high thrust motor.
 

Bruiser

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Vapor doesn't make a good upgrade to 29mm. You'll either need to enlarge the fins or add weight to the nose (or a little of both) for most 29mm motors. How do I know? Been there and done that. Them build thread is here on TRF. Go with a Star Orbiter and you'll be miles ahead.

-Bob
 

Jay Rairigh

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When a fin pops off on landing or careless handling, the glue holds and the paper tears. The glue does not give way.

I almost always use TTW construction because I've had some hard landings AND I've been careless in handling. With TTW I have never had a fin do anything except stay put.

To each his own.
 

teepot

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I would go with TTW. It helps stiffen the fin can, adds support to the mmt to help stop it from taking off thru the rocket. It also give you two attachment places to keep the fins on.
 

bill_s

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Star Orbiter came first and is designed for 29mm from the beginning. The Vapor is a Hobby Lobby exclusive and uses nearly all the same parts except for 24mm and different fin shape. You can get a Star Orbiter for $15 from ACSupply so nearly the same cost as the Vapor.


When comparing them, the Star Orbiter is the better rocket. It is slightly longer and so more stable, it has TTW fins standard and will fly on anything from BP E16 motors to APCP G motors without modification and beyond if you tweak it slightly. I have flown a Star Orbiter on a G54 that also had a Eggtimer Quark in an Apogee av-bay to make it dual-deploy. If you think the F44 was impressive, pop a big G in the Star and have your socks blown off. You could upgrade the rings to lite-ply and put an H180 in it and go supersonic and over a mile high if you wanted.
Well Hobby Lobby was out of the Star when I went by and I really didn't want it anyway. Lost sight of the Vapor twice last weekend on E12s. Zero interest in putting an H180 in it.
 

Back_at_it

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Well Hobby Lobby was out of the Star when I went by and I really didn't want it anyway. Lost sight of the Vapor twice last weekend on E12s. Zero interest in putting an H180 in it.
Completely agree. I don't understand the fascination of flying out of sight. I'm on my third Apogee Aspire now and don't see myself ever flying that on anything larger than a D motor as it's completely out of sight. The first one was lost on an E30 and the second on an E9. Unless I'm trying to set some personal record, I don't see the point. A nice 1500-2000ft flight is more than enough for me.
 

CalebJ

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I don't believe Hobby Lobby actually sells the Star Orbiter, for what it's worth. They have a pretty stripped down version of the overall Estes catalog, plus a few that are made specifically for them.
 

Ez2cDave

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If you want to try something from "Back In The Day", there is the "Interlap Method" . . . It's "labor-intensive", but VERY strong !

Dave F.

FIN ATTACHMENT METHODS.jpg



INTERLAP - 1.jpeg



INTERLAP - 2.jpeg


TUBE CUTTING PATTERN.jpg
 
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Bruiser

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Hobby Lobby stopped carrying the Star Orbiter a year or two ago when they stopped carrying the 29mm motors. It was a sad day :(

Now the go-to place for a Star Orbiter (and most Estes) is AC Supply

-Bob
 

Ez2cDave

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That looks both tedious and awesome !
That is a great description . . .

BTW - On minimum diameter rockets, I like to insert a stage coupler, or a reload casing, with a layer of wax paper, to prevent the glue from entering the "motor mount".

On HPR models, JB WELD works VERY WELL, in this application !

Dave F.
 
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