Estes Vapor

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The fins in the kit don't look to be big enough for stable flights so I enlarge them to what I think will be better.
 

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Bill S

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Mine has been a great flier. I have a second one that I plan to build at some point. Only change would be to put an BT-50 stuffer tube in it; I have had several fail to eject parachute incidents... And I can say definitely no matter what Rocksim says, don't use C11 engines in it... learned that one the hard way.

Estes Vapor.JPG
 

dpower

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Huh, seems like it should fly OK on a C11-3, at 8.6 ounces - not very high, though! I agree that the fins are plenty big enough. I really need to get one of these.
 

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I'm only going to fly this one on E12 only reason to change the fins. Thanks for the input.
 

GlenP

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Looks like you are building two of them, what is the grain direction on the stock kit, did you attach those fins on the correct root edge? Hard to see the grain lines in the picture. I thought the root edge should be the hypotenuse edge.
 
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TigerHawk

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On page 65 of the new 2022 Estes catalog I think they mistakenly show the Vapor fins on the PSII Star Orbiter?
 

lakeroadster

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Looks like you are building two of them, what is the grain direction on the stock kit, did you attach those fins on the correct root edge. Hard to see the grain lines in the picture. I thought the root edge should be the hypotenuse edge.

Good call Glen.. you have eagle eyes.

fins.jpg
 

Bill S

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Huh, seems like it should fly OK on a C11-3, at 8.6 ounces - not very high, though! I agree that the fins are plenty big enough. I really need to get one of these.

One would think the C11 would be okay, particularly since Rocksim said ok flight, but two consecutive flights on C11-3s led me to think bad idea. Both flights resulted in bad ejection (one didn't eject at all, the other somehow tangled up on the fins), resulting in tail-first crashes that damaged the engine mount and tube.

I've also flown it primarily on 15" w/4" spillhole thin-mil parachutes from Top Flite. The 18" parachute included will result in a lot of drift, especially if you plan to use the E12 engine.

"Is the Vapor still only a hobby lobby exclusive? "
Yes as far as I know. Good to get a spare.
 

TigerHawk

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I didn’t even know the catalog was out. But yes, how strange.

View attachment 501293

You don’t suppose they’re changing the actual Star Orbiter kit?
I think there’s a post on YORF about it from John Boren (Designer @ Estes) and he says it’s a mistake because there’s no changes to the PSII Star Orbiter.
 

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Looks like you are building two of them, what is the grain direction on the stock kit, did you attach those fins on the correct root edge? Hard to see the grain lines in the picture. I thought the root edge should be the hypotenuse edge.
You are correct. I made the mistake of gluing them on wrong so I cut 6" off the tube to salvage it. I will glass the fins and to make up for the grain issue. Good eyes.
 

GlenP

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You are correct. I made the mistake of gluing them on wrong so I cut 6" off the tube to salvage it. I will glass the fins and to make up for the grain issue. Good eyes.
I mainly noticed the fin profile looking different. It might make more sense to put the larger fins on the shortened tube model, but probably enough stability margin in the design that makes no adverse impact either way. Looks like a great kit, enjoy the builds!
 

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Not clear why you think the stock fins are inadequate. Have you tried simulating it?
I read a post in mid power about a gentleman having stability issues with the Vapor with F motors and blamed the fins. So with that in mind is why going bigger fins. I like the looks better with the larger fins as well.
 

PigHeaded

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I fly mine with E motors with no issues. Wonder how the bigger fins will actually affect stability.
 

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I fly mine with E motors with no issues. Wonder how the bigger fins will actually affect stability.
I don't think it's going to be a problem. Once CG is established should fly good. Might not get the altitude you get but that's ok with me.
 

GlenP

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You could maybe use a removable nose weight, so you can balance it for the larger F motors, but remove it for use with the stock kit recommended D and E motors. Just if you might need the flexibility for different sized fields.
 

Scott_650

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Good to know.

Still, that might be a fun mod to it.
I’ve been thinking about a Vapor finned SO since I saw the erroneous catalog picture - bashing a HL Vapor and a Hi-Flier XL looks doable - plenty of balsa in the Hi-Flier kit to cut down the fins with TTW tabs using the Vapor fins as patterns plus the Hi-Flier with it’s original fins is way over stable so it’s a good recipient for those Vapor fins 😎

But, on the other hand, I already have plenty of built and unbuilt 3/4FNC rockets…eh, rockets are like jello - there’s always room for more 😆
 

GlenP

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Rocksim reports a stock Vapor with a CTI 6-grain G motor has 2.74 calibers of stability (and over 3700').
Just to clarify. This is the 24mm mount LPR Vapor, which is basically similar to the MPR 29mm motor Star Orbiter. Both are kits designed for Estes black powder. When you start going beyond that, those balsa fins might shred, I don’t have this personal experience but there are some older threads to that effect. So upgrading the fins with ply, glass for higher than kit-rated power is likely required. Making the fins larger is perhaps not required for stability, but reinforcing them structurally for strength and flutter resistance is essential, when you start using larger than the recommended Estes black powder motors for the stock kit. In fact, making the fins larger without reinforcing them structurally can make the fin flutter problem worse beyond the kit rated motors.
 

John Taylor

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The fins in the kit don't look to be big enough for stable flights so I enlarge them to what I think will be better.
It is stable with the stock fins. Some people have put them on backwards and it's still stable. Making them larger will indeed make it more stable moving the CP aft. Looks fine!
 

smstachwick

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Just to clarify. This is the 24mm mount LPR Vapor, which is basically similar to the MPR 29mm motor Star Orbiter. Both are kits designed for Estes black powder. When you start going beyond that, those balsa fins might shred, I don’t have this personal experience but there are some older threads to that effect. So upgrading the fins with ply, glass for higher than kit-rated power is likely required. Making the fins larger is perhaps not required for stability, but reinforcing them structurally for strength and flutter resistance is essential, when you start using larger than the recommended Estes black powder motors for the stock kit. In fact, making the fins larger without reinforcing them structurally can make the fin flutter problem worse beyond the kit rated motors.
I bet it’d be fine on a G25W or something like that. Something with nice low thrust.
 

GlenP

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I bet it’d be fine on a G25W or something like that. Something with nice low thrust.
Ask @CPUTommy
 
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