Performance Rocketry Mongoose 75

gtm3323 said:

For all the money you spent on the rocket, why not go with a classier (or more costly) altimeter? Let me explain. I like PF don’t get me wrong they are really easy to use and work well, but the data and functionality that you recover from it is minimal. But on the other hand like RDAS, ARTS2, LCX, ADEPT ect, have many more functions and can recover lots of data from it. I am also aware space is limited but I have an ARTS2 and LCX and they probably could fit. Sorry if I offend anyone but I am all about mixing and matching altimeters (cheap one with expensive one)

My 1 cent (dwindling economy),

Gerald Jr.

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No offense taken on my end.

Yes, I might use some sort of flight computer and a PF MAWD, or maybe not. The fact is I have used PF electronics exclusively over the years and I -trust- them. I haven't heard of any issues using dual MAWDs. Have you experienced problems? If so, I'd like to hear about them.

In an earlier post I stated I had both PF MAWDs and HiALT45s, potentially using one of each. If I decide to add another type of altimeter or flight computer to the arsenal, I'll need to give it a few flights in a test rocket before I'm comfortable using it in my Mongoose.

I'm in no hurry to complete this rocket, and serious consideration will be given to both recovery electronics and deployment methods before it takes to the air.

Much work has been done to the Mongoose in the past few days.

All of the carbon fiber has been applied. The carbon fiber lay-up was the only part of this build that I was concerned with. Once cured I took the Mongoose to the shop for some finish work. With some 80-grit sandpaper on my Bosch random orbital sander and Shop-Vac attachment I trimmed the excess carbon fiber off the body tube and fins, including the bevels. Then used 80-grit sandpaper and hand-sanded the carbon fiber that was over the fin can/body tube. No pictures of the sanding though. It's tough to sand & take pictures with a respirator on.

The cool thing for me is when I was done sanding I took the rocket outside and washed it off with a garden hose. I didn't have my camera at the time 'cause I was being bombarded by wasps that were hold-up in my hose reel. I didn't get stung so that's a good thing. :surprised:

It looked great when wet though! I can't wait to get some clear on this thing.

Later I added another fillet between the fins and the body tube as you can see in this picture.

Next I'll coat the fin bevels with a layer of Pro-line epoxy for a little heat protection.

Lookin great Kevin...can't wait to see it person, I'll bet it is sweet. Better yet, I can't wait to see it fly!!

Johnnie

Rocket Guy 1317 said:

So when does it get the KBA M1450W?

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Well, I have to finish BUILDING IT before I fly it.

I do like the white motors and currently I'm thinking of a AMW M1350WW. That's my #1 motor choice right now.

I'll admit the KBAs have my attention, but I haven't seen one in person.

Scalded Tiger?

kaycee said:

Well, I have to finish BUILDING IT before I fly it.

I do like the white motors and currently I'm thinking of a AMW M1350WW. That's my #1 motor choice right now.

I'll admit the KBAs have my attention, but I haven't seen one in person.

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Well having seen the M1450 in flown a 75mm minimum diameter to 37K I have to say it's a really nice a motor. I've also flown the AT M1850 for the 75/7680 casing in my Performance Rocketry Competitor 4 to 18,600 feet and change. Looking good.

EDIT: -removed-

Rocket Guy 1317 said:

EDIT: A rocket like this deserves nothing but the best and Aerotech/RCS motors are the best motors on the market.

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Do they pay you to say all of this? They better, because you're doing more advertising in threads than they do at launches...

The build is looking good, I am playing with the idea of buying a Mongoose 54...

Rocket Guy 1317 said:

Aerotech/RCS motors are the best motors on the market.

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Having watched someone waste 4 ignitors trying to get an Aerotech motor to light, I gotta say its CTI for me

No I'm not getting paid to say any of this. I've flown for the most part nothing but Aerotech, yes I've flown an AMW I315SK and J440BB and two Loki I110's in Nevada, but you can't fly AWM or Loki in California.

So in California we have Aerotech and CTI.

CTI classic propellant just bores me, compared to White Lightning. I've never really had any problems getting an Aerotech to light either.

EDIT: sorry kevin for hi-jacking the thread. The building is looking great so far.

Rocket Guy 1317 said:

EDIT: sorry kevin for hi-jacking the thread. The building is looking great so far.

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No problem. Thanks also!

Back to the business at hand. Tonight I taped off the fins and body tube and added a layer of Pro-Line epoxy on the fin bevels to add an extra layer of heat protection to the fins.

Tomorrow I'll fair-in the leading and trailing edges of the fins using the same epoxy. Once cured I'll do a little sanding to shape and smooth everything in preparation of the last build step before the clear coat is sprayed. That last step will be a special one.

There's much more to come!

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Looking forward to seeing this 'special' step!

When do you plan on flying her Kevin? I might have to make a trip to Huntsville- lemme see, it's only about a 9 hour drive...:rotflol:

Darn, forgot to ask my question

How did you get the carbon so neat next to the body tube?

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Pantherjon said:

Looking forward to seeing this 'special' step!
When do you plan on flying her Kevin? I might have to make a trip to Huntsville- lemme see, it's only about a 9 hour drive...:rotflol:

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I've not planned that far ahead, but will shoot for sometime this flying season with the PMW gang. It's just south of Talladega, so it's probably a shorter drive for you.

init 6 said:

Darn, forgot to ask my question

How did you get the carbon so neat next to the body tube?

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I used peel-ply on top of the carbon fiber cloth and wet it out with resin. It was my first time to use carbon this way, so I was a little aprehensive going in. It turned out to be surprisingly easy to work with though. See post #56.

Today I sanded the fillets to shape then mounted the 'goose on the rotisserie for the final application of laminating resin. I mixed up a small batch of Aerpooxy and covered the body tube just north of the fins to the back edge. I had a bit of trouble with the way I mounted the rocket in that the motor would stop every few minutes, so I'll be turning it by hand for the next few hours. After the epoxy cures, I'll lightly sand the tube and then the clear goes on. Here's what it looks like after ~2 hours.

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Oh my. If that's just the epoxy, then the final coat of clear will make the rocket look absolutely gorgeous. Good job.

Edit: Let me rephrase that. Great job.

Today was the big day. Temperature & humidity were perfect for a day of spraying some clear. After a final sanding and cleaning of the rocket with prep-sol, I mixed up some 2-part Dupont automotive clear and 'shot my 'goose'. Here is the result.

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Oh, one other thing. I purposely did not clear the nose cone. I like the way it looks as-is, plus the clear would burn off it anyway.

That's pretty much the build. All that's left is to add rail buttons and decide on what harnesses, chutes, D-bags and what not to use for recovery.

I'd say you did alright.

Far and away one of the cleanest applications of CF I have seen in a long time. Looks great!

little bit of paste wax and that thing will have a 12" shine

Ben

DPatell said:

I'd say you did alright.

Far and away one of the cleanest applications of CF I have seen in a long time. Looks great!

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Gee thanks! The application of the carbon fiber was a little tedious, but very rewarding.

ben said:

little bit of paste wax and that thing will have a 12" shine

Ben

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Thanks Ben. Actually I plan to whet sand the airframe with 1200-2000 grit in the next few days and then buff it out for a really slick finish.

Wow, I love the shine. I can't wait to see what it looks like after the wet sanding and buffing.

jj94 said:

Wow, I love the shine. I can't wait to see what it looks like after the wet sanding and buffing.

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Thanks Josh. Gotta take it up one more notch.:surprised:

That really does look good. I have a similar project waiting for my at home (I am at college), it's a PR component FG 3" minimum diameter rocket. I regret the fact that I cut the 48" main tube to fit just a 76-3600 motor and a zippler-less coupler. I would never fly a 4800 or 6000ns motor in it, but I just wish I had kept it that configuration.

I applied CF T2T just as you did, and mine didn't come out nearly as good as yours. I wish I had your patience!

DPatell said:

That really does look good. I have a similar project waiting for my at home (I am at college), it's a PR component FG 3" minimum diameter rocket. I regret the fact that I cut the 48" main tube to fit just a 76-3600 motor and a zippler-less coupler. I would never fly a 4800 or 6000ns motor in it, but I just wish I had kept it that configuration.

I applied CF T2T just as you did, and mine didn't come out nearly as good as yours. I wish I had your patience!

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You can always buy another PR tube, sit back and rethink your build. As has been said many times, build your rocket to the largest motor that will fit. You can always adapt down, but very difficult to adapt up.

As for the carbon fiber, I owe much of my success on this build to my son, Kyle. He has researched composite strengthening, construction and advanced lay-ups for several years, and is well-schooled on the subject. I am not, so looked to him for help with my 'goose. As they say, you're never too old to learn. I am proof of that.

And as for Kyle, he's in the process of building his L3 rocket. It is a modified PR Competitor 5. It is scheduled to fly at Southern Thunder 2009, just after his 18th birthday in May.

The main reason I maxed out the size of the motor is because I am on the East Coast. Secondly, I did it for a reason that you will probably have issues with as well...positive motor retention. I designed and implemented a system for fore motor retention for both 76mm motors and a 76-54 adapter.

Looking back I should have just tossed those out the window for the generic friction fit and eyebolt on top of the motor!

kaycee said:

That's pretty much the build. All that's left is to add rail buttons and decide on what harnesses, chutes, D-bags and what not to use for recovery.

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Not going to launch it out of a tower on a KBA M3500. Very nice looking build. Whats the final weight?

pyrovette20 said:

Not going to launch it out of a tower on a KBA M3500. Very nice looking build. Whats the final weight?

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Empty weight without recovery or electronics is 6#. She's a lean machine for sure.