Lakeroadster's F-79 Lone Wolf

[BABAR]

First, stable flight proves the design. Very nice.

Second, agreed nylon chutes optimal.

You can rig plastic chutes with shroud lines going over chute apex (there is an Apogee video on this.). It greatly increases strength without much increase in volume.

Overall however, I think the key is, as you said, shorter delay. Us “black powder” guys don’t always get those perfect apogee ejections the electronics guys do.

When does the Shark fly? Or did I miss it?

 

[Woody's Workshop]

Not many rockets come in at that high of velocity and have many parts reusable.
How a rocket is built often makes it heavier.
You have demonstrated perfectly why a strongly built rocket is worth it's weight!
Bravo Sir!

 

[BABAR]

But most important of all, did you get the penny (nickel) back?

 

[lakeroadster]

I always loved this game.....

 

[lakeroadster]

When does the Shark fly? Or did I miss it?

We flew it last week...

https://www.rocketryforum.com/threads/lakeroadsters-hammerhead-shark.157283/page-10#post-2293464

But most important of all, did you get the penny (nickel) back?

No penny weighted streamer used on the F-79 rocket. We did use one on the Mercury LES rocket and the Hammerhead... and both were recovered.

 

[Daddyisabar]

With the 5 second delay delay you did get some nice glide time! Bah humbug on the wimpy conservatives who say use short delays on oddroc first flights. Airplane rockets must glide at high speeds! Very cool.

Bulletproofing rules! Bigger motors rule!

 

[lakeroadster]

With the 5 second delay delay you did get some nice glide time! Bah humbug on the wimpy conservatives who say use short delays on oddroc first flights. Airplane rockets must glide at high speeds! Very cool.

Bulletproofing rules! Bigger motors rule!

Per Open Rocket, without a chute the ground hit speed is 92 mph.

And I believe it, The Lone Wolf was howling... and then, the tone deafening silence.

 

[Daddyisabar]

Per Open Rocket, without a chute the ground hit speed is 92 mph.

And I believe it, The Lone Wolf was howling... and then, the tone deafening silence.

The worst part is when, during the tone defining silence, you hear the distinctive thud of terminal impact. The sound of the internal air pressure blowing your body tube and nose cone to bits. Seeing the dust rise on the big ones it is time to break out the pick and shovel.

 

[Dane Ronnow]

Per Open Rocket, without a chute the ground hit speed is 92 mph.

If the only damage was the front of the nose cone—which actually looks kind of cool—I'd say you've got your impact-resistant build technique down pat. Kudos all the way around.

 

[burkefj]

With the 5 second delay delay you did get some nice glide time! Bah humbug on the wimpy conservatives who say use short delays on oddroc first flights. Airplane rockets must glide at high speeds! Very cool.

Bulletproofing rules! Bigger motors rule!

Bah on bulletproofing and nasty old clusters, Just make it glide, man up and be the pilot in command, and get rid of nasty old parachutes, gentle flare to landing at your feet makes the girls go crazy

 

[lakeroadster]

You can rig plastic chutes with shroud lines going over chute apex (there is an Apogee video on this.). It greatly increases strength without much increase in volume.

That's a great idea. I've watched that video but never thought to do that. This would be a valid option. Thanks.

Is the long coupler, item 6 on sheet 3, for structural reinforcement? If so, I think it's overkill, unnecessary weight. As we all know, most LP rockets use stock tubes with no such reinforcement and do fine, unless they dirt dive. Will the coupler add enough strength to survive such an event? Is that your purpose?

I saw this ^^^ post over on my Ahpla build and thought about how the F-79 wasn't damaged by a 90-mph dirt dive due to the full-length internal coupler... and the hardwood nose cone.

If you're not building for altitude... one might as well make it "Hell For Stout".

 

[Daddyisabar]

Bah on bulletproofing and nasty old clusters, Just make it glide, man up and be the pilot in command, and get rid of nasty old parachutes, gentle flare to landing at your feet makes the girls go crazy

Yes, but I want good looking, sports scale, piston engined fighters an bombers 1914 to 1945! Only by giving into the Dark Side can I fly the rockets I love.

Oh won't you save me...GI Joe! Now if you remember that commercial jingle you are old as dirt! Kung-fu grip rules!

 

[lakeroadster]

I unbolted the nose cone from the F-79 today. It's removable to clean out any ejection charge bits. There isn't a clear path, the ejection gasses do a 180 degree turn for the rear eject and the burning hot bits impale on the nose cone.

Yowza. What the heck am I looking at here? A lot more chunks of stuff than I expected.

Since this flies on dual D12's is it possible the first motor that fired the ejection charge fouled the second motor? Or is this just normal?

 

[Joshua Smith]

Wow, that's impressive. Maybe they stagnated each other at the top which let the hot bits stay there longer? I mean, that looks like it was actually on fire for a bit

 

[Daddyisabar]

Some of the poopy clay plugs have a lot of bits and your design catches all of two motors worth. Normal forward ejection design they mostly just blow out the top.

 

[lakeroadster]

Wow, that's impressive. Maybe they stagnated each other at the top which let the hot bits stay there longer? I mean, that looks like it was actually on fire for a bit

.... at the suggestion of some TRF members I coated the inside of the Main Body and Side Pods with thinned down Gorilla Glue. Hoping to minimize any damage due to ejection gasses and hot bits related thereto

 

[Daddyisabar]

Rocket Scientists, always trying to keep their rockets from melting. Oh, such a cruel world!

 

[lakeroadster]

Rocket Scientists, always trying to keep their rockets from melting. Oh, such a cruel world!

It's a tip I got from some witch I met out west here.

 

[Joshua Smith]

On baffles I put a layer of wood glue, or epoxy depending on the situation, on the primary contact surface. After it dries, I then spray it with some high temp rattle can paint just for good measure. I usually use black because that's what I usually have on hand and it hides the soot lol

 

[Lee]

Has anybody tested to see what type of glue is most heat resistant?

 

[Daddyisabar]

No glue coating will stand up to the power of burning powder. I constantly resoak with thin CA and it burn, burn, burns with every launch. I tell the Top Men it is an ablative coating, but they know I am not a rocket scientist, just a silly liberal arts major flying airplane rockets and shaping my fins with fire in flight.

 

[Lee]

That’s direct exposure to the main motor burn - no surprise there. With rear ejection, I’m wondering about the MMT and other internals (stuffer tube) being affected by the ejection charge. I’m thinking a wad of steel wool will absorb some of the ejection charge, but what about the glue that’s holding everything together?

 

[lakeroadster]

That’s direct exposure to the main motor burn - no surprise there. With rear ejection, I’m wondering about the MMT and other internals (stuffer tube) being affected by the ejection charge. I’m thinking a wad of steel wool will absorb some of the ejection charge, but what about the glue that’s holding everything together?

The ejection charge is an instantaneous blast.

When I bench tested the F-79 the body tube was warm to the touch but wasn't hot enough to burn my bare hand. It would stand to reason that the fin can glue joint and base materials are in more danger of heat induced issues from the hot motor casing, as a result of the motor burning, than the areas that take the ejection charge blast / pressure wave.

 

[lakeroadster]

You can rig plastic chutes with shroud lines going over chute apex (there is an Apogee video on this.). It greatly increases strength without much increase in volume.

I found the video, here's a link: Strengthen Plastic Parachutes for Model Rockets - Running Shroud Lines Over the Top of the Chute

I think I'll give this a try for flight No. 2

 

[BABAR]

O

The ejection charge is an instantaneous blast.

When I bench tested the F-79 the body tube was warm to the touch but wasn't hot enough to burn my bare hand. It would stand to reason that the fin can glue joint and base materials are in more danger of heat induced issues from the hot motor casing, as a result of the motor burning, than the areas that take the ejection charge blast / pressure wave.

i have had minimum diameter rockets with the old black powder quest motors where the OUTSIDE of the body tube around the motor visibly browned. Clearly from the hit casing, not the ejection charge.

 

[lakeroadster]

A Stronger Pair of Parachutes.

Backstory

One of the two Estes 18" chutes I used on the F-79's maiden flight shredded away from the shroud lines, and the other chute never blossomed due to heat damage from the ejection charge.​

The Easy Upgrade That Isn't Possible

I figured I'd just upgrade to nylon for the next flight. Today I tried to pack the 18" nylon chute that I have into the BT-50 recovery tube in the F-79, there's just not enough volume for it.​

Babar & TVM To The Rescue

Following @BABAR 's advice & the Apogee Video I set about to make some better lightweight parachutes for the F-79.​

​

Starting with a couple 18 in 1.5 mil poly chute kits w/swivels that I bought from BMS, I then used 75lb Kevlar as the shroud lines and for tape used 3m clear shipping tape.​

​

I followed TVM's video but the tape sticks great to the chute but doesn't stick at all to the Kevlar. So, to keep the Kevlar from slipping I tied the chords to the chute also.​

​

This should work as long as I can get them to eject from the tubes without being melted by the ejection blast. Thus far I've melted (3) chutes out of (4). I may wrap the chutes with crepe paper this time.​

 

[BABAR]

A Stronger Pair of Parachutes.

Backstory

One of the two Estes 18" chutes I used on the F-79's maiden flight shredded away from the shroud lines, and the other chute never blossomed due to heat damage from the ejection charge.​

The Easy Upgrade That Isn't Possible

I figured I'd just upgrade to nylon for the next flight. Today I tried to pack the 18" nylon chute that I have into the BT-50 recovery tube in the F-79, there's just not enough volume for it.​

Babar & TVM To The Rescue

Following @BABAR 's advice & the Apogee Video I set about to make some better lightweight parachutes for the F-79.​

​

Starting with a couple 18 in 1.5 mil poly chute kits w/swivels that I bought from BMS, I then used 75lb Kevlar as the shroud lines and for tape used 3m clear shipping tape.​

​

I followed TVM's video but the tape sticks great to the chute but doesn't stick at all to the Kevlar. So, to keep the Kevlar from slipping I tied the chords to the chute also.​

​

This should work as long as I can get them to eject from the tubes without being melted by the ejection blast. Thus far I've melted (3) chutes out of (4). I may wrap the chutes with crepe paper this time.​

View attachment 529200View attachment 529201View attachment 529202View attachment 529203

This may sound like a crazy idea, and I haven’t tried it, but you may be able to sew the Kevlar through the plastic chute. Allows you to skip the tape. The tape will add a bit of bulk.

 

[lakeroadster]

This may sound like a crazy idea, and I haven’t tried it, but you may be able to sew the Kevlar through the plastic chute. Allows you to skip the tape. The tape will add a bit of bulk.

Not crazy at all, thanks for the idea. That might work, but the Kevlar is so slick it just slides through and then wants to bunch up the chute. That's why it had to be tied to the corners, the chute would just slide up the Kevlar toward the "north pole".

I used really small pieces of shipping tape, 3/8" square (ish), so it really doesn't add much to the bulk. But the shipping tape really sticks great to the chutes.

 

[lakeroadster]

2nd Launch of the F-79

Pretty uneventful flight. The pilot thought he was supposed to land on the runway.

This rocket is pretty beautiful, and under thrust is rock solid. No coning or other phenomenon's that can happen with a lot of nose weight.

I wish both chutes would have blossomed... oh well.

The photo of the F-79 on the asphalt... that's not staged... that's actually where it landed and how it looked when we walked up to it.




The Money Shot

 

[Daddyisabar]

Rockets have a nose to land on the only surface in the park. Hopefully missing the speeding bicyclist coming out of no where.