5.5" Cherokee-D L3 build thread for rharshberger

kjkcolorado said:

Just curious. Why a LiPo for the Quark, but a 9V for the RRC3?

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The RRC3 I have many flights on with a 9v, and no issues. The Quark I have never flown yet, only tested with LiPo's, they are configurations known by me to perform in an expected manor. Eventually I will switch entirely to LiPos.

Wow Rich. This is really coming along nicely.

Rich,,
Check the fit of a quick link on those eyes..
With the quick links in place try to put a motor case in from the bottom...
Check that the motor case clears the quick links...
You may have to use U bolts instead of eyes to eliminate the quick links...

Teddy

onebadhawk said:

Rich,,
Check the fit of a quick link on those eyes..
With the quick links in place try to put a motor case in from the bottom...
Check that the motor case clears the quick links...
You may have to use U bolts instead of eyes to eliminate the quick links...

Teddy

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One step ahead on that one already, motor contact is not likely as the motor is 75mm and the MMT is a 98mm. I will be changing to 1/4" eyebolts which are smaller, the 5/16" are too large and according to max shock loads the 1/4" may deform but should be well below failure point. Its interesting how large the 5/16" are compared to the 1/4". Thanks for the thought, I may still go with U-bolts.
I don't currently plan to fly 98mm motors in the near future, but I may eventually so I build for the largest motor that will reasonably fit.

If the motor mount is 98 mm then check for clearance with a long 98 mm case...
Just to be certain you're not building in a restriction,,, no ??

Teddy

onebadhawk said:

If the motor mount is 98 mm then check for clearance with a long 98 mm case...
Just to be certain you're not building in a restriction,,, no ??

Teddy

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You are correct Teddy, but I do not have access to a 98mm case, a coupler if I have one will do the same thing, and is easier to obtain from local fliers.

Oh man,,
I have a Aerotech 98 / 2560 shorty...
I'd have sent it to you with the harnesses if I'd have known...
Sorry Rich...

Teddy

Hey,, you're right though...
A coupler will show you the same thing....

onebadhawk said:

Oh man,,
I have a Aerotech 98 / 2560 shorty...
I'd have sent it to you with the harnesses if I'd have known...
Sorry Rich...

Teddy

Hey,, you're right though...
A coupler will show you the same thing....

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That mmt is long enough to handle a 98/7680 without extending past the top of the tube. mmt is 25.5" long. A 98/10240 might have a issue with the current configuration though.

The Fins are in the bag....literally the Vac Bagging setup.

Learned a lot from this process.
A) Cut the material with plenty of extra at least a 1/2" per edge extra or enough that the tape used to keep the fraying from occuring can be cut off later.
B) The tape used to prevent fraying, forget about getting it off even if you made it less sticky by sticking it to your shirt first.
C) A Rotary cutter with cutting mat is indispensable for cutting composite fabrics, no need to pick the fabric up or shift it to cut like with scissors.
D) A FoodSaver with a few mods can do even the big jobs OK, not great but OK.

The Vac attachment is a bag adapter from ACP sales ($14), simply use a punch and carefully cut a hole in the bag for the adapter, it uses a nut and washers to seal and is meant for 1/8" tubing. The black tubing is micro or drip irrigation line, its not really flexible, but its hard and wont collapse under vacuum, its also cheap, and I have lots of it on hand anyways. The black line also is a perfect fit for the canister adapter on the FoodSaver as can be seen in the second photo. I did add a ball valve to shut off the vacuum from the FoodSaver when done pulling down.

The bag seals are re-usable and purchased from ACP as well.





Edit: with the exception of the peel-ply and breather, the vac bag setup is generally re-usable if treated kindly, while not in use.

I'm surprised that works. Thanks for sharing. Now I have another vacuum option available.

rharshberger said:

The RRC3 I have many flights on with a 9v, and no issues. The Quark I have never flown yet, only tested with LiPo's, they are configurations known by me to perform in an expected manor. Eventually I will switch entirely to LiPos.

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Thanks for the input. My current DD setup is the RRC2+ with 9V. I'm thinking of switching to LiPo, that's why I asked.

dixontj93060 said:

I'm surprised that works. Thanks for sharing. Now I have another vacuum option available.

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I was too, Tim. It seems to have worked just fine though. The real surprise was finding a simple tubing that would work without searching forever. I de-bagged the fins this morning, photos to follow.

rharshberger said:

I was too, Tim. It seems to have worked just fine though. The real surprise was finding a simple tubing that would work without searching forever. I de-bagged the fins this morning, photos to follow.

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Yeah, I like that; low cost components.

my wife just bought a food saver, she saw left overs....I saw rocket application! Good job, thanks for the info I case i go that route.

And in Nick's house the other night---------
Nick---
Nick,, what is it---
Nick,, why are you starting at my new food saver like that.....

lol..

Teddy

onebadhawk said:

And in Nick's house the other night---------
Nick---
Nick,, what is it---
Nick,, why are you starting at my new food saver like that.....

lol..

Teddy

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Our FoodSaver has been in the shop for a couple of weeks and Teri (my wife) still hasn't realized its missing, from the kitchen cabinet.

hahahahahahaha,,,
That's too funny man....

Yeah,,
But your wife Teri had hers a while...
The novelty had worn off...
Nicks wife just got her new toy,,,
and,,,
hey wait a minute,,,
it was right here last night,,
I know it was,, I was messing around with it...

Teddy

rharshberger said:

Our FoodSaver has been in the shop for a couple of weeks and Teri (my wife) still hasn't realized its missing, from the kitchen cabinet.

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One day while I was at work my wife went downstairs and pulled two sieves off my storage shelf to use in cooking. When I got home I asked her about them. She said, "yes, I needed them to cook the lasagna..." I had to mention that one had AP written on the underside of the handle and the second "Metals". She was not too happy as she threw out two large Pyrex baking dishes of lasagna. :y:

onebadhawk said:

hahahahahahaha,,,
That's too funny man....

Yeah,,
But your wife Teri had hers a while...
The novelty had worn off...
Nicks wife just got her new toy,,,
and,,,
hey wait a minute,,,
it was right here last night,,
I know it was,, I was messing around with it...

Teddy

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Its also not canning season yet at my house, if it was....trouble indeed.

dixontj93060 said:

One day while I was at work my wife went downstairs and pulled two sieves off my storage shelf to use in cooking. When I got home I asked her about them. She said, "yes, I needed them to cook the lasagna..." I had to mention that one had AP written on the underside of the handle and the second "Metals". She was not too happy as she threw out two large Pyrex baking dishes of lasagna. :y:

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OOuuuccchhhhhhhh.....

But I thought for canning you just use masons jars...

Teddy

onebadhawk said:

OOuuuccchhhhhhhh.....

But I thought for canning you just use masons jars...

Teddy

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Not canning, just cooking. She was pissed.

dixontj93060 said:

One day while I was at work my wife went downstairs and pulled two sieves off my storage shelf to use in cooking. When I got home I asked her about them. She said, "yes, I needed them to cook the lasagna..." I had to mention that one had AP written on the underside of the handle and the second "Metals". She was not too happy as she threw out two large Pyrex baking dishes of lasagna. :y:

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Ouch! indeed, that kind of event usually requires much grovelling and begging for forgiveness on my part.

As for canning, yes its really just mason jars we use for that, but around my house we use the term pretty much for anything related to long term produce storage, even drying peppers.

Worked a bit more on the fins and mmt today.

Fins are out of the vac bag and for the most part look OK, the triangular panels even though sanded smooth still imprinted under the pressure of the bag. One of the triangle panels did shift a bit which will require some filler. The only thing I gained by the composite construction was a stiffer fin, and a very small loss in weight (composite fins are about 1oz lighter than solid ply fins). The resin:fabric ratio is about 1:1 (there is actually by weight 16grams less epoxy than carbon). The weight loss of course will be offset by the additional filler needed to smooth the fins.



View attachment 284768View attachment 284767

Part2 of today, some work on the MMT.

First up: The booster shock cord attachment points. I wanted the eye bolts to be removable so being unable to get weld nuts of the appropriate size I modified T-nuts and put wood screws through the tabs into the ring, so that nothing moves when the eye bolt is removed. Not shown are the eye bolts themselves which are now the next size smaller than the previous ones and much better fit.

On to the rings, the forward most CR is slotted one side only, the center one is slotted both sides, and the rear one is slotted one side only and pilot drilled for the threaded inserts that mount the thrust plates and eventual AeroPack 98 retainer. The drilling/marking template in the 5th picture I made using OpenRocket, the triangular cuts in it are for lining up the ID since there was no center mark. The rings were cut for me by Pacific Steel, Pasco, Wa (a former employer of mine). The plasma cutter did a nice job, the I.D.s are dead on and the OD's are just a bit under the airframe diameter, aluminum can be tough to plasma even with a CNC system like Pac Steel has. The mockup of the thrust plate in the 7th photo is with a 54mm DMS L1000W, hopefully by next month this motor will be used for the check flight on this rocket. The last photo is one of the fins with both of the thrust plates for this rocket, the thrust plates will also act as part of the motor adapters.

Those fins are gorgeous - very nice work. All around the level of precision involved with this build is mighty impressive.

Are you going to be flying the Cherokee-D at NXRS? I would love to see it!

By the way, I actually like the look of the triangles showing through the CF cloth. In this case it might not be the look you are going for, but I could see doing something like this where the inset is done from a thinner material than the frame.

FITS is my planned cert flight however NXRS has not been ruled out, things are starting to move along now.

Totally can't wait to see this fully assembled! Excellent work Rich.

Unbelievably meticulous work Rich,,,
Just gorgeous man..

Teddy

Teddy said:

Check that the motor case clears the quick links...
You may have to use U bolts instead of eyes to eliminate the quick links...

Click to expand...

In the instance that a quick-link would cause an obstruction, I'd use a bowline knot. I use those all the time.

Rich said:

The only thing I gained by the composite construction was a stiffer fin, and a very small loss in weight (composite fins are about 1oz lighter than solid ply fins).

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I think you gained a LOT stiffer fin that what you realize over a solid plywood fin. If you've never used end-grain balsa before (and no, I didn't read through the entire thread to know better) CF or even just FG laid over 1/4" or 1/2" end-grain balsa makes for a seriously freakin stiff panel. I learned about the stuff back when I sold boats. A lot of boat manufacturers use it in their hulls to save weight. At least they use to. A lot use Divinycell now. You can make the entire fin out of it if you have a good means of edging the fin. I think your fins look great and turned out great just the same though. I've also made extremely light weight bulkheads and centering rings from end-grain as well. Think of the stuff like using I-beam construction.

I really miss having the time and space to do stuff like this. I'm happy to see people still practicing the art of hand laying fiberglass on paper tubes. This thing should fly great on a wide variety of motors as compared to the now all too common heavy all FG tanks out there. Ahhhh the good ol days!

Loki Research said:

In the instance that a quick-link would cause an obstruction, I'd use a bowline knot. I use those all the time.



I think you gained a LOT stiffer fin that what you realize over a solid plywood fin. If you've never used end-grain balsa before (and no, I didn't read through the entire thread to know better) CF or even just FG laid over 1/4" or 1/2" end-grain balsa makes for a seriously freakin stiff panel. I learned about the stuff back when I sold boats. A lot of boat manufacturers use it in their hulls to save weight. At least they use to. A lot use Divinycell now. You can make the entire fin out of it if you have a good means of edging the fin. I think your fins look great and turned out great just the same though. I've also made extremely light weight bulkheads and centering rings from end-grain as well. Think of the stuff like using I-beam construction.

I really miss having the time and space to do stuff like this. I'm happy to see people still practicing the art of hand laying fiberglass on paper tubes. This thing should fly great on a wide variety of motors as compared to the now all too common heavy all FG tanks out there. Ahhhh the good ol days!

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Thanks Scott for your kind words. The amazing thing so far is that the original pre-build Open Rocket sim was 29lbs, currently the build sim with the known weights is at 29.9Lbs, I am sure the paint and the epoxy will add at least 2 more pounds prior to being finished. The fins are indeed stiff, and they do have less deflection than the regular baltic birch version. I like building FG over cardboard, and as I get better at it the weights continue to come down. I have lots of end grain balsa left to play with and several upscales forthcoming that would be prime for a composite fin like my 5" Mega Mosquito, or the 5" Fatboy, and a 3" Aries SST. Sadly all of those will be a ways out, since most of the next year will be building a new house, and selling the current one.