HotRod Rockets - Fruit Fly

[CharlaineC]

hmmm now i'm thinking of adding to my shock cord another few inches. though i used heavy duty nylon inplace of the kevlar

 

[JAL3]

hmmm now i'm thinking of adding to my shock cord another few inches. though i used heavy duty nylon inplace of the kevlar

I'm going off of memory here since I don't have the instructions in front of me.

I think the Fruit Fly came with Kevlar only, no elastic, and that the Kevlar was longer than the elastic that comes with most kits. I installed the Kevlar and then tied on about 10" of sewing elastic.

On the first flight, it looked like the Kevlar had sawed through the elastic although the Kevlar did look a bit frayed afterwards. On the second flight, the Kevlar broke about halfway along its length.

The problem with putting much more is that there will be no room to pack it.

I'm still thinking it over and need to order another NC.

 

[HotRod Rockets]

I'll reply here so others can see and offer advise if they wish.
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Jal, these very small rockets can be a challange huh! Not much room at all to put in the recovery stuff, coupled with the occaisonal "very energetic ejection" on the 13mm motors.

I'll dig through my stack o' stuff and send out a replacement nosecone... cause I feel bad for such a purty rocket.

I Do have a question on the sepperation. Was it at the knot? (where the Kevlar meets the elastic). Or did the Kevlar cut through the elastic?

I try, in all very small rockets, to not wrap the Kevlar around the elastic when prepping just because of that.

Just curious.

David

 

[JAL3]

I'll reply here so others can see and offer advise if they wish.
-------
Jal, these very small rockets can be a challange huh! Not much room at all to put in the recovery stuff, coupled with the occaisonal "very energetic ejection" on the 13mm motors.

I'll dig through my stack o' stuff and send out a replacement nosecone... cause I feel bad for such a purty rocket.

I Do have a question on the sepperation. Was it at the knot? (where the Kevlar meets the elastic). Or did the Kevlar cut through the elastic?

I try, in all very small rockets, to not wrap the Kevlar around the elastic when prepping just because of that.

Just curious.

David

Yup. It shore do get tight in there.

I'd love to have a genuine replacement NC and am willing to pay for it. Since the kit is OOP, I thought I might have to use a balsa substitute.

On the first flight, it broke right at the knot. It looked to me like Kevlar sawing through the elsatic. The streamer had been wound with the elastic but not the Kevlar, and inserted. THe Kevlar just got pushed in any old way on top.

On the second flight, it was a matter of the Kevlar snapping well aft of where the know was. I cannot give a diminsion because the NC and its stringie things have gone bye-bye.

 

[HotRod Rockets]

O.key.

I'll send sumthing out tomorrow for you to try with that nose cone. Balsa nose by the way wont work, too light. The Only way that flys right is with the heavy cone.

I just have to dig through my boxes of stuff. I think I purchased so much stuff at Narcon it may take some time to get re-organized.

.

 

[JAL3]

O.key.

I'll send sumthing out tomorrow for you to try with that nose cone. Balsa nose by the way wont work, too light. The Only way that flys right is with the heavy cone.

I just have to dig through my boxes of stuff. I think I purchased so much stuff at Narcon it may take some time to get re-organized.

.

I'm in no hurry. Take your time. I suspect that this coming month is going to see very little rocket activity from me with Easter coming up and the grand opening of a new church. Also, pm me with what I owe.

 

[evil ed]

Don't sweat it Hotrod. I got him covered on the cones.

 

[abw]

Very nice! How does it compare to an Estes 220 Swift? I have one and I like the way it looks, but it shoots off too quickly when you actually launch it...

 

[JAL3]

Very nice! How does it compare to an Estes 220 Swift? I have one and I like the way it looks, but it shoots off too quickly when you actually launch it...

I had a 220 Swift. It was not the first rocket that I built as a BAR but it was the first one I launched. It was on a 1/4A3-3. I never saw it again.

This one is a bit longer and a bit heavier. You can actually see it fly. It has the potential to get lost but is not guarenteed to get lost. I managed to watch it on both a 1/4A and a 1/2A. With the 220 like the Mosquito, I never actually saw it fly; it was just there and then it wasn't.

 

[CharlaineC]

found an 1/2a3-2 yesterday while rearanging my rockets and hope to fly mine if this wind dies down. I'm going to add a small barrel swivel and see if it helps

 

[JAL3]

I got my replacement NC from HotRod a couple of days ago and decided it was time to get to work on the replacement. I want to keep this one for a while since it is the smallest I have managed to launch and recover.

 

[JAL3]

The NC was primed with white and given a day to dry.

 

[JAL3]

The NC was then sprayed with a metallic purple which has never worked well for me before. It still doesn't look metallic but its the best this paint has looked for me.

 

[TheAviator]

JAL,

A little suggestion that may help alleviate some of your ejection problems:

Run your shock cord in the competition streamer model manner. Set your Kevlar in one of the fin root edges with enough hanging down the back to stretch to the end of the model. Then using white glue, glue the cord into the root fillet. For packing, run the cord up the side of the rocket, then next to the nose shoulder and down in. You may need to slot the side of the nose cone or the tube for this to work well. However, you will reduce some of the ejection forces just via the geometry. It also makes the cord easily replaceable if need be.

Because this is a minimum diameter model, I assume that you need to tape the motor in. Use that extra length of Kevlar sticking down below the fin to give it a little security, and wrap your tape around the cord as well as the motor and tube.

 

[CharlaineC]

that is how the shock courd is mounted on this rocket

 

[TheAviator]

that is how the shock courd is mounted on this rocket

:blush: Oops, I see that now... Anyways... your problem then, is probably insufficient wadding; Kevlar will "burn through." It just takes longer. The burn through is not actually a burn in this case, but a chemical destruction of the Kevlar.

 

[JAL3]

:blush: Oops, I see that now... Anyways... your problem then, is probably insufficient wadding; Kevlar will "burn through." It just takes longer. The burn through is not actually a burn in this case, but a chemical destruction of the Kevlar.

Point taken about the Kevlar. I actually used a longer piece than came with the kit but used dog barf instead of wadding. When I replace it, I will problably use the next heavier grade of Kevlar and make a point to have some real tissue wadding present.

I was going to do that tonight but duty called and I forgot to check the caller ID.:confused2:

 

[HotRod Rockets]

This kit has very littel room to pack everything.

Best bet method, small "cup" of sheet wadding pushed in to tube first. Then a bit of barf. Then wrap all the revovery goodies in a "recovery burito" with a bit of sheet wadding on the outside.

But, as with any very small rocket packing takes practice.

Another hint, sometimes I shorten the streamer. The streamer really only slows down the nose cone on this one. Makes more eficent use of the very limited space.

Hope this helps.

?What the heck was the guy who designed this thinking?


.

 

[JAL3]

This kit has very littel room to pack everything.

Best bet method, small "cup" of sheet wadding pushed in to tube first. Then a bit of barf. Then wrap all the revovery goodies in a "recovery burito" with a bit of sheet wadding on the outside.

But, as with any very small rocket packing takes practice.

Another hint, sometimes I shorten the streamer. The streamer really only slows down the nose cone on this one. Makes more eficent use of the very limited space.

Hope this helps.

?What the heck was the guy who designed this thinking?


.

I think he was thinking how much fun it would be to have me running around clueless.

THanks for the advice.

 

[JAL3]

The purple for the nosecone did not turn out as I expected but it was certainly much nicer than I have gotten this particular paint before. While I was hoping that it would actually have a metallic appearance, like some insects, it came out as more of a glazed candy. Still, I am satisfied.

 

[JAL3]

I cut off the stub of the old Kevlar and then went to my stash and got a 36" length of Semroc's at the next grade up. I put a knot in the end to help prevent it from pulling out.

 

[JAL3]

CA was then used to anchor the Kevlar to the root edge of the notched fin with the knotted end towards the top. Yes, that's right, the long end was facing aft. I had trouble getting things to stay in place so I shot it with a does of CA accelerant.

 

[TheAviator]

John,

If this rocket has a motor block, the easy way to tell if you have a good seal is to roll your wadding up (crepe paper streamer works great for this size rocket) and put in the top of the tube (don't push it all the way down.) Then blow the wadding down into the tube, sealing your lips over the top of the rocket. If it slides down in when you do this, you have a good seal. If it doesn't, take it out and try again.

If it doesn't have a motor block, you'll need to catch the wadding with your finger before it slides out the back end. Just put a finger in the other end to keep it from popping out, or your test means nothing.

This technique works with any size rocket.

 

[JAL3]

An hour or so later, I laid in a fairly substancial fillet of white glue along the top of the Kevlar and set it aside to dry.

 

[JAL3]

The next day, I wrapped the Kevlar around the base of the fin and again tacked it into place with CA. When that had dried, I laid a white glue fillet along the root.

 

[JAL3]

The glue fillets shrank, of course, and did not completely cover the shock cord. Upon inspection, I decided that such was not at all out of character with this rocket since threads had been used for texture on the fins. As such, I applied some cellophane tape to mask the Kevlar and started spraying the repaired area with the copper paint.

 

[JAL3]

Upon getting home after most of the week out of town, I removed the tape from the Kevlar and tied the Kevlar to the nose cone. The knot was fixed with a spot of yellow glue. When that had dried, I packed it up. All it lacks is a streamer for next' Saturday's launch.

 

[JAL3]

The Fruit Fly got another outing today after the repairs. IT was the first flight of the day and took off on a 1/4A3-3. The flight was perfect and it recovered without a problem.

A grainy flight video can be seen here: https://www.flickr.com/photos/23694991@N03/3623284859/

 

[JAL3]

The Fruit Fly also showed up at my birthday launch. I loaded it with a 1/2A3-2 and packing the streamer did not get any easier with age.

 

[JAL3]

At ignition it screamed upwards and, by all accounts, had a pretty fair flight. I was too slow to see it until one of the kids fetched it back for me. The NC stuck and it lawndarted but there was no damage.