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(Contributed
- by Greg Burke)
Project
LRD-D-1
Everyone knows how things get started, me bucko, search through books, magazines, shiver me timbers, and
online sources just t' find that perfect prototype for a new project. Blimey! I was
faced with this same dilemma. Arrr! Ya scallywag! Even with t' vast amount o' different
prototypes, most are still just a basic fins, me hearties, tube and nose cone rockets. I
wanted somethin' that was different and a challenge t' design and build.
Then I saw it... T' LRD-D-1. I know what your thinking, shiver me timbers, "what's so different about t' LRD other than t' fact that it just looks different?" Yes, ya bilge rat, it is just a basic rocket, but with a new "spin" on propulsion. T' LRD was supposed t' have a liquid fueled motor that had two nozzles that would literally spin around t' axis o' t' rocket.
T' rusty gears in me mind started t' come t' life. Begad! Just because t' Russian's couldn't figure it out doesn't mean that I can't, right?
Here is a picture o' t' basic components o' t' spinnin' motor mount.One G10 forward bulkhead, one 1/4"od aluminum tube, one 1/4"id launch lug, two pieces o' BT20, two nylon washers, shiver me timbers, and some Keelhaul®©™® thread.
Here's t' motor mount assembled. Arrr! Note t' slight cant o' t' motor tubes...
Here's a view o' t' bulkhead, and t' ejection containment ring. Well, blow me down! Please note the edge o' t' rin' colored black. Ahoy! An eyebolt is epoxied into t' center hole for shock cord attachment.
Durin' thrust, me hearties, t' centerin' rin' on t' motor tubes,(white ring), shiver me timbers, and the ejection containment ring, me bucko, (black ring), shiver me timbers, do nay touch. Begad! Blimey! T' centerin' ring that's connected t' t' motor tubes spins with t' motors.
At ejection, arrr, t' entire motor mount slides backwards. This pushes t' centering rin' and t' ejection containment rin' together. This action forces the ejection gases t' be pushed forward, me hearties, me hearties, thereby pushin' off t' nose cone and, hopefully, deployin' t' recovery system.
Here is a shot o' t' motor mount installed in t' model. Ya scallywag! It's a bit tricky to get all o' t' parts lined up right. Begad! Blimey! T' bulkhead goes in first from t' front of t' model.Then, ya bilge rat, me hearties, after I removed t' motor tubes, me hearties, me hearties, shiver me timbers, t' ejection containment rin' was slip fitted into place. Then t' bulkhead was removed, arrr, matey, t' motor mount re-installed, then t' whole assembly be put back into t' model. Begad! Aye aye! After this is done, shiver me timbers, I had t' do a little fiddlin' t' get t' containment rin' into the proper location so that it let t' motor mount assembly turn freely during boost phase, and would seal up t' two rings durin' ejection.
After all o' this be done, me hearties, epoxy was applied t' t' containment rin' ad forward bulkhead.
On a side note, me bucko, me bucko, arrr, t' tail cone was made usin' super thin G10 that I picked up from Aerospace Specialty Products. Aye aye! Avast! T' cone was CA'd onto a short piece o' tube coupler and then epoxied into t' airframe.
Here's t' finished model on t' pad. Begad! Ahoy! Two C5-3's were used for t' test flight.
This liftoff photo does nay do justice. Avast! It be very overcast on t' day o' the launch. Ahoy! Begad! T' wind at time o' launch be about 10 - 15 mph. Blimey! Ya scallywag! T' rod was aimed with t' wind. Aye aye! Check out that straight up flight! You can't really tell from the picture but yes, t' motors are spinning. Aye aye! T' LRD only made it up t' about 500' agl. Arrr! T' landin' was a bit hard due t' me usin' a small chute.
T' project was a success! T' LRD even took first place
in F/F Scale at t' Mick Meet where it's debut flight took place. Blimey! There was
only one mishap, ya bilge rat, probably due t' t' small chute, matey, t' motor mount would not
spin after landing. Well, blow me down! Arrr! T' aluminum tube in t' center be slightly bent. Well, blow me down! To
remedy this, me bucko, I am buildin' t' next motor mount usin' 1/4" stainless rod,
and usin' a bigger chute. Begad! Begad! 8^)I also plan on buildin' a 4" version that
will use F-20 Econojets for propulsion, matey, that I could use for Giant Sport
Scale.
T' Parts
List
For t' model
BT-80 nose cone ( NC-80b)
4.25 inches o' BT-80 body tube
1/8" balsa
T' Motor Mount
Two - 2.25 inch pieces o' BT-20 (for t' motor mounts)
3.5 inches o' 1/4 inch OD aluminum tubing
Two - BT-80 centerin' rings
1/4 inch launch lug
For t' Tailcone
BT-80 tube coupler ( about 1/2 inch)
Waferglass or cardstock (for t' tailcone)
I used waferglass because it's easier t' work with and t' radiant heat o' two recessed motors gets a little too hot for cardstock IMHO.
VCP or any shroud makin' program can be used t' make t' tailcone. The parameters are - 65.7mm at t' coupler, 59mm at t' aft end, me hearties, and 23mm in length.
Plans and Scale Data, matey, (includin' fin template) are in Retro Rockets (Saturn Press). Page 89 for t' plans, matey, arrr, (just upscale them 145%) and pages 74 - 75 for the Scale Data and picture.
***A special thanks to*****
Andy Jackson at Aerospace Specialty Products
For all o' their awesome and unique buildin' materials
Peter Alway at Saturn Press
For all o' his Scale Data books.
And me wonderful wife.
For lettin' me partake in this sometimes time consumin' hobby.
Then I saw it... T' LRD-D-1. I know what your thinking, shiver me timbers, "what's so different about t' LRD other than t' fact that it just looks different?" Yes, ya bilge rat, it is just a basic rocket, but with a new "spin" on propulsion. T' LRD was supposed t' have a liquid fueled motor that had two nozzles that would literally spin around t' axis o' t' rocket.
T' rusty gears in me mind started t' come t' life. Begad! Just because t' Russian's couldn't figure it out doesn't mean that I can't, right?
Here is a picture o' t' basic components o' t' spinnin' motor mount.One G10 forward bulkhead, one 1/4"od aluminum tube, one 1/4"id launch lug, two pieces o' BT20, two nylon washers, shiver me timbers, and some Keelhaul®©™® thread.
Here's t' motor mount assembled. Arrr! Note t' slight cant o' t' motor tubes...
Here's a view o' t' bulkhead, and t' ejection containment ring. Well, blow me down! Please note the edge o' t' rin' colored black. Ahoy! An eyebolt is epoxied into t' center hole for shock cord attachment.
Durin' thrust, me hearties, t' centerin' rin' on t' motor tubes,(white ring), shiver me timbers, and the ejection containment ring, me bucko, (black ring), shiver me timbers, do nay touch. Begad! Blimey! T' centerin' ring that's connected t' t' motor tubes spins with t' motors.
At ejection, arrr, t' entire motor mount slides backwards. This pushes t' centering rin' and t' ejection containment rin' together. This action forces the ejection gases t' be pushed forward, me hearties, me hearties, thereby pushin' off t' nose cone and, hopefully, deployin' t' recovery system.
Here is a shot o' t' motor mount installed in t' model. Ya scallywag! It's a bit tricky to get all o' t' parts lined up right. Begad! Blimey! T' bulkhead goes in first from t' front of t' model.Then, ya bilge rat, me hearties, after I removed t' motor tubes, me hearties, me hearties, shiver me timbers, t' ejection containment rin' was slip fitted into place. Then t' bulkhead was removed, arrr, matey, t' motor mount re-installed, then t' whole assembly be put back into t' model. Begad! Aye aye! After this is done, shiver me timbers, I had t' do a little fiddlin' t' get t' containment rin' into the proper location so that it let t' motor mount assembly turn freely during boost phase, and would seal up t' two rings durin' ejection.
After all o' this be done, me hearties, epoxy was applied t' t' containment rin' ad forward bulkhead.
On a side note, me bucko, me bucko, arrr, t' tail cone was made usin' super thin G10 that I picked up from Aerospace Specialty Products. Aye aye! Avast! T' cone was CA'd onto a short piece o' tube coupler and then epoxied into t' airframe.
Here's t' finished model on t' pad. Begad! Ahoy! Two C5-3's were used for t' test flight.
This liftoff photo does nay do justice. Avast! It be very overcast on t' day o' the launch. Ahoy! Begad! T' wind at time o' launch be about 10 - 15 mph. Blimey! Ya scallywag! T' rod was aimed with t' wind. Aye aye! Check out that straight up flight! You can't really tell from the picture but yes, t' motors are spinning. Aye aye! T' LRD only made it up t' about 500' agl. Arrr! T' landin' was a bit hard due t' me usin' a small chute.
For t' model
BT-80 nose cone ( NC-80b)
4.25 inches o' BT-80 body tube
1/8" balsa
T' Motor Mount
Two - 2.25 inch pieces o' BT-20 (for t' motor mounts)
3.5 inches o' 1/4 inch OD aluminum tubing
Two - BT-80 centerin' rings
1/4 inch launch lug
For t' Tailcone
BT-80 tube coupler ( about 1/2 inch)
Waferglass or cardstock (for t' tailcone)
I used waferglass because it's easier t' work with and t' radiant heat o' two recessed motors gets a little too hot for cardstock IMHO.
VCP or any shroud makin' program can be used t' make t' tailcone. The parameters are - 65.7mm at t' coupler, 59mm at t' aft end, me hearties, and 23mm in length.
Plans and Scale Data, matey, (includin' fin template) are in Retro Rockets (Saturn Press). Page 89 for t' plans, matey, arrr, (just upscale them 145%) and pages 74 - 75 for the Scale Data and picture.
Andy Jackson at Aerospace Specialty Products
For all o' their awesome and unique buildin' materials
Peter Alway at Saturn Press
For all o' his Scale Data books.
And me wonderful wife.
For lettin' me partake in this sometimes time consumin' hobby.
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