Well guys I have been tossing around ideas about what rocket to build for my L1 and I think I have settled on a 5" DerRedMax. I want to go with a 5" to a keep the alt down for my small field (the club flys up to L2 there I just want to be comfortable) and be able to do my L2 with this rocket when we make one of our trips to NC. does anyone hve the dimensions for a 5" DRM or is willing to help me upscale it. I dont have rocksim yet. I can make my own centering rings and nosecones on my lathe if I have too. I am going to do ttw fins and glass them for strength might even glass the tube. we launch at an air field and there is lots of concrete runways to remove your fins for you. I want to put a gps in this as well or some kind of tracking system.
1st upscale 5" DRM
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zog43editor
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That's about a 4.3x upsacle going on the BT-60's 1.637" diameter.
The oriiginal DRM tube (BT-60HE) was 8.5" long so you're looking at 36.55" of tubing.
Your cone is gonna be about 28.38" long from tip to shoulder. That's a big meatball!
I think the fin dimensions are listed on JimZ's page for the DRM, here's the link- just multiply them by 4.3 to fit.
https://dars.org/jimz/estes/est0651e.tif
Sounds impressive.
Good luck with your project!
kj
The oriiginal DRM tube (BT-60HE) was 8.5" long so you're looking at 36.55" of tubing.
Your cone is gonna be about 28.38" long from tip to shoulder. That's a big meatball!
I think the fin dimensions are listed on JimZ's page for the DRM, here's the link- just multiply them by 4.3 to fit.
https://dars.org/jimz/estes/est0651e.tif
Sounds impressive.
Good luck with your project!kj
TeenRocketNerd
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I wouldn't turn a cone that big out of wood and use it- most L1 motor wouldn't even lift it with a safe 5:1 ratio. If you're going to turn your own, I would glue up a foam blank, turn that slightly smaller than your final dimensions, and glass over the foam with a few layers of fiberglass. Then, use acetone to disolve the foam, glue in a ply bulkhead with forged eye bolt, and giddy up.
Scotglas is a company that makes custom fiberglass cones, if you aren't confident in your own glassing abilities.
With your flying area (concrete) I would be inclined to do tip to tip on the fins to keep flutter on those huge fins down, and to protect them from harsh landings.
just my 2 cents.
Scotglas is a company that makes custom fiberglass cones, if you aren't confident in your own glassing abilities.
With your flying area (concrete) I would be inclined to do tip to tip on the fins to keep flutter on those huge fins down, and to protect them from harsh landings.
just my 2 cents.
wow thats one heck of a first scratch build it will be 5 feet 4 inches tall. well you know what they say you only live once I am going for it. it should be a good show. I am going to glass the wings tip to tip and I am thinking of glassing the tube. I already have a gallon of west systems resin just need to get some glass any recomendations on what weight of glass to use? what size ply should I use for the fins? I have a 36" planer so I can adjust the thickness if I have to.
Hogan3276
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You're going to need to be careful of the weight on this one...if you use too much glass - your L1 motor may struggle to lift this one safely.
I wouldn't worry too much about the fin flutter...the issue is the landing. With I, J & K motors - the rocket will not fly fast enough for flutter issues. If you put an L in that one - well that's another story...
My L2 rocket was a 6" DRM. I made the fins from 1/4 ply - no glass at all. Flew it on a J415 - never had any issues with fin flutter - but on landing those big fins like to dig into the ground or in your case will hit hard on the concrete...
I am not saying that you can't or shouldn't glass the fins...if I did it would have saved me from the stress marks from landing.
I started using a small coffee can attached to the bottom of the rocket - this acted as a crush can and once I started using this - I didn't have any more stress marks.
I attached this to another DRM thread last week - but here is a pic of mine with the can attached.
However, I did glass my 8" Version - but that one will be flying with an M in it so in that case - the fins may flutter a bit...
I wouldn't worry too much about the fin flutter...the issue is the landing. With I, J & K motors - the rocket will not fly fast enough for flutter issues. If you put an L in that one - well that's another story...
My L2 rocket was a 6" DRM. I made the fins from 1/4 ply - no glass at all. Flew it on a J415 - never had any issues with fin flutter - but on landing those big fins like to dig into the ground or in your case will hit hard on the concrete...
I am not saying that you can't or shouldn't glass the fins...if I did it would have saved me from the stress marks from landing.
I started using a small coffee can attached to the bottom of the rocket - this acted as a crush can and once I started using this - I didn't have any more stress marks.
I attached this to another DRM thread last week - but here is a pic of mine with the can attached.
However, I did glass my 8" Version - but that one will be flying with an M in it so in that case - the fins may flutter a bit...
Hogan3276
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As for the nosecone - making your own is certainly one way to do it...either by using foam and glass or by Balsa and glass...or if you can find a 5" - 5 to 1 Ogive - then all you need to do is cut off the tip and make it rounded (I used an easter egg, glass and bondo)...you'll have a cone that is very close to the original DRM cone.
Good luck with this one. It is a lot of fun to fly...They fly pretty low and slow with this those big fins...my 6" Version with a J only went to about 1200'. Mine had some weight to it though...
Good luck with this one. It is a lot of fun to fly...They fly pretty low and slow with this those big fins...my 6" Version with a J only went to about 1200'. Mine had some weight to it though...
hazegray, I would go with a 54mm mount in a 4". It will stay plenty low untill you max it out on a K my dads Loc caliber weighed 5lbs and went 907 feet on an H123. This thing will prolly only get 750-800'. I would really think about a 4" unless you are wanting to use 38/600 loads on up for a good flight.
Ben
my dads Loc caliber weighed 5lbs and went 907 feet on an H123. This thing will prolly only get 750-800'. I would really think about a 4" unless you are wanting to use 38/600 loads on up for a good flight.Ben
Rocketjunkie
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5"/1.637" is almost exactly 3x, not 4.3x. It is still a pretty good size
also, found this,
https://www-personal.umich.edu/~mbear/redmax.html
Used it on my fatboy and will use it on my Der Red Max(s)
Ben
https://www-personal.umich.edu/~mbear/redmax.html
Used it on my fatboy and will use it on my Der Red Max(s)
Ben
Ben the goal is to be able to get really good flights as you put it later on. The guys I fly with go to NC and you know I tried to get to Red Glare this year but that didnt work out. so its going to be a 54mm engine mount scaled down for cert flights to 38mm so I can do them at the local field. Thanks for the link I am sure it will come in handy. I ORDER PARTS THIS WEEKEND!!!! gonna get this puppy started
Ben the goal is to be able to get really good flights as you put it later on. The guys I fly with go to NC and you know I tried to get to Red Glare this year but that didnt work out. so its going to be a 54mm engine mount scaled down for cert flights to 38mm so I can do them at the local field. Thanks for the link I am sure it will come in handy. I ORDER PARTS THIS WEEKEND!!!! gonna get this puppy started
ok. I would like to go down to NC sometime. I plan on making a 5" one to test my idea for the 11.5" so Maybe we can drag.
Ben
rokitflite
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karl66
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zog43editor
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5"/1.637" is almost exactly 3x, not 4.3x. It is still a pretty good size
yeah- no clue how I messed that up with the calculator, must have fat fingered it. :0
Fore Check
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I say go for it
If you're worried about weight on a L1 motor, don't forget - an I600R or a CTI I540WT is a "L1 motor." No-one says you have to cert L1 on the lowest impulse H motor you can find....
If you're worried about weight on a L1 motor, don't forget - an I600R or a CTI I540WT is a "L1 motor." No-one says you have to cert L1 on the lowest impulse H motor you can find....
well guys I am looking into motor casings and stuff right now. I am thinking about using a Loki case they do not have a I300 however they do have the following.
I316 - The delay time is adjustable from 5 to 17 seconds. I316-SF Spitfire 1.5 sec 465 N-s 38-480 $37.99
I405 - The delay time is adjustable from 5 to 17 seconds. I405-LW Loki White 1.2 sec 480 N-s 38-480 $29.99
I110 Moon burner - Delay adustable from 5 to 12 seconds **requires #16 nozzle** I110-LW Loki White 4.0 sec 484 N-s 38-480 $32.99
I430 - The delay time is adjustable from 7 to 15 seconds. I430-LB Loki Blue 1.2 sec 520 N-s 38-480 $29.99
So what do you guys think? or do I need to build the rocket first then weigh it to decide on a motor. My club has a leup and mail orders all of our engines we do not have a vendor onsite
I316 - The delay time is adjustable from 5 to 17 seconds. I316-SF Spitfire 1.5 sec 465 N-s 38-480 $37.99
I405 - The delay time is adjustable from 5 to 17 seconds. I405-LW Loki White 1.2 sec 480 N-s 38-480 $29.99
I110 Moon burner - Delay adustable from 5 to 12 seconds **requires #16 nozzle** I110-LW Loki White 4.0 sec 484 N-s 38-480 $32.99
I430 - The delay time is adjustable from 7 to 15 seconds. I430-LB Loki Blue 1.2 sec 520 N-s 38-480 $29.99
So what do you guys think? or do I need to build the rocket first then weigh it to decide on a motor. My club has a leup and mail orders all of our engines we do not have a vendor onsite
I would build it first then weight it. I do think the I430 Loki blue would be your best bet. Its a good size I with alot of thrust! I do think as long as you don't COMPLETELY overbuild it you will be fine.
The I430 will lift 19lbs at a 5:1.
Ben
I know Patrick at CNC rings -n- Fins has DRM fins for a 5.5" tube. Order from him and get your CR's he is the lowest that I know of!
Ben
fastfreddie
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Seriously, make sure you sim it out for max velocity before you fly it. At NARAM this year a guy I know flew his 3" DRM on an AT H242 and it shredded at about 100 feet. I myself have flown a 5" upscale Goblin with unglassed 1/4" ply fins on a Loki J528 and a HT K240 with no problems, but it was dual deploy, and pretty heavy, so the max velocity was pretty slow.
very true. I hardly worry about that sometimes because I build heavier anyways so thy won't break on landing. On the DRM I would suggest glassing the fin with maybe a layer of 6oz. Because they are swept past the BT they will take the first grunt at landing. Unless you plan on bringing it down at 14FPS or less they could start cracking fillets after 3-4 flights.
Ben
I am going to glass the tube and tip to tip the fins. the tube is a philonic tube from red arrow hobbies. I might use a bit of chopped glass in the fillets for added strength. I was toying with the idea of using chopped CF but I think that would be a bit expensive. The field I fly at is very unforgiving so I am trying to build it strong.
just a note,
www.commonwealth.net
They have phenolc tubing from CDI and they have alot more stuff (IMHO) and I know you will get it (not saying Red Arow is bad just giving you more options
)www.cstsales.com
Has all the composites you need and sales on some of it so that might be your ticket.
Didn't know what your plans where but I always liekt o throw other sites out there because sometimes its just what you need!!
Ben
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