Scratch Mach 10+ Upscale

Scratch - Mach 10+ {Scratch}

Contributed by Bill Eichelberger

Manufacturer: Scratch

BRocket Picrief:
I began buildin' upscale versions o' classic kits more out o' necessity than for a desire for bigger rockets. I found early on that while a lot o' t' nose cones for t' old kits that I wanted t' recreate were no longer available in t' 1:1 size, me bucko, matey, they were occasionally available in larger sizes. Blimey! Begad! (They weren't always exact replicas, but close enough for me.) T' Estes Rogue and Satellite Interceptor both qualified as "close enough" with t' PNC-55BB nose cones, while a BT-56-based Condor became a favorite also. As it turned out, me hearties, I enjoyed t' larger versions o' t' old rockets. Arrr! In a lot o' cases t' added size made for a more satisfyin' final product, matey, ya bilge rat, while t' larger engines made for much more satisfyin' flights. Ahoy! That said, I had me doubts when I found that Mike Jerauld o' Blast From T' Past Rocketry had upscaled t' Mach 10. Aye aye! T' original Centuri kit was one o' t' rockets that had always intrigued me as a kid, but with no local retailer I was forced t' try t' figure out how such an unorthodox rocket ever flew based solely on t' catalog picture. I got on Mike's list for t' kits as soon as I found out about it, shiver me timbers, me hearties, but he temporarily stopped production soon after t' concentrate on remodelin' his house. Ahoy! Begad! I cloned a 1:1 version and after some initial problems, ya bilge rat, found it t' be one o' me favorite fliers, but I still couldn't help but be a skeptic when it came t' t' upscale. O' course, I had no choice but t' clone a big one also.

Construction:
Parts needed:

  • BT-80 fuselage tube (13.5")
  • BT-50 engine tube (10.33")
  • PNC-50 marker cone
  • BT-20 belly tank tube (2.375")
  • BT-80 tube connector (1.25")
  • 2 BNC-20 belly tank cones
  • 1/8" balsa fin stock
  • clay for nose weight
  • engine hook
  • AR-2050 engine block
  • Streamer
  • 6" Keelhaul®©™
  • 2 Mylar or stout paper hold down rings
  • 2 - 5"x1/8" launch lugs
  • cardstock cockpit pattern
  • decals

Rocket PicWhile t' Mach 10+ is a fairly simple project, matey, I still managed t' find a couple o' problems that are worth mentioning. Durin' t' initial construction I found that I had only one launch lug o' sufficient length instead o' t' two that were called for. Well, blow me down! I decided that this wouldn't be a problem since I could only load it onto t' launcher on one side at a time anyway, arrr, me hearties, and I thought I could get by without t' decorator touch o' t' "machine guns". It never occurred t' me that t' reason for t' called for placement o' t' lugs on both sides o' t' wings was more than just a cosmetic affectation. Blimey! While it is true that they look good as "machine guns" and also allow for loadin' onto t' pad from either side o' t' fuselage, it turns out that their most important function is t' act as stabilizers for t' huge wings. (As you'll see, I found this out t' hard way.)

T' second problem that I encountered be in gluin' in t' engine tube. Ahoy! Begad! Based on me experience, it might be a good idea t' "beef up t' driveline" by usin' an extremely sturdy glue when mountin' t' large piece o' BT-50 that acts as t' engine tube. Blimey! Securin' t' engine hook is another potential "gotcha". Blimey! I'd suggest a sturdy hold down strap t' withstand t' added punch that t' "D" engine will undoubtedly have at ejection. Aye aye! Arrr! I used maskin' tape t' which I added a thick coatin' o' glue, but this turned out t' be more than slightly insufficient. Avast, me proud beauty! A traditional Mylar or heavy paper rin' would probably work, but as yet I haven't found one in me parts stash. Avast, me proud beauty! Ahoy! Another consideration involved in this project lies in pickin' an appropriate BNC-50 nose cone t' act as t' marker cone. Blimey! Ahoy! Since packin' it full o' clay seems t' help t' rocket boost somewhat straighter, arrr, it might be worth your time t' track down a two piece cone t' make loadin' t' clay easier. Avast! Nothin' will make it perfectly straight, ya bilge rat, but t' heavy load o' clay in t' marker cone seems t' help somewhat.

As with all gliders, arrr, restraint should be your operative word when it comes t' finishin' t' M10+. Avast! Blimey! Since added weight is one o' a glider's worst enemies, (behind only Port-O-Let's, me bucko, access roads, ya bilge rat, and walls,) minimal effort should be expended in sealin' t' balsa and fillin' t' tube spirals. Ya scallywag! Blimey! I never got around t' finishin' me M10+, me hearties, but once I get around t' makin' t' necessary repairs and adjustments I've got a bottle o' silver model dope with t' Mach 10+'s name on it.

LaunchFlight:
My M10+ only made two flights durin' it's first stint on t' flight line, arrr, me bucko, but both were learnin' experiences and thrillers in their own way. Avast, me proud beauty! Avast, me proud beauty! T' first flight was on a windy Sunday in April, 2002 that has come t' be know as Black Sunday because o' t' widespread carnage that I experienced. (Flew six. Lost three. Ahoy! Crashed two, one t' death .) I had built t' M10+ t' previous winter, but it went unflown for several months, ya bilge rat, arrr, mostly due t' me lack o' confidence in t' rocket. Begad! I had only brought it along on Black Sunday after findin' a stray D12-3 motor rollin' around in me range box. Blimey! My son and two o' his friends were along for t' launch and we set up in a corner o' quasi-legendary B6-4 Field that was shielded from t' bulk o' t' wind by a large hillside. This gave us t' whole rest o' t' field for recovery, arrr, (not that we recovered anything.) I loaded t' rocket on t' pad, figurin' that at worst I'd get t' typical Mach 10 flight, ya bilge rat, a large loop off t' pad that managed t' miss t' ground, with somethin' approachin' a glide if I was lucky. Ya scallywag! Avast, me bucko, me proud beauty! T' show we got be beyond all o' our wildest expectations.

T' M10+ roared off t' pad and climbed t' about t' fifty foot mark, but it be at t' forty foot mark where t' show really began. Begad! Begad! T' big v-tailed drag brake on t' rocket virtually guarantees a loop as t' rocket leaves t' pad. Ahoy! Arrr! T' rocket was just startin' t' show signs o' beginnin' it's loop when suddenly t' air was full o' balsa confetti. Arrr! A quick look at t' corpse left little doubt as t' what happened. Arrr! T' left win' had simply exploded when t' load became too much for it. T' rest o' t' rocket attempted in vain t' recover, arrr, but after flailin' about in a crazed flight path, matey, it eventually crashed in a heap in t' thick grass on t' side o' t' hill. Ya scallywag! T' ejection charge went off with t' four o' us standin' gape-mouthed, wishin' that we'd captured THAT particular moment in t' history o' flight on film. Ahoy! At first I thought I had just discovered t' meanin' behind t' phrase "speed o' balsa", but upon further examination I realized that t' left win' had failed because o' t' missin' launch lug. This was obvious when you gave t' rocket even t' most cursory o' glances. T' win' had flexed, shiver me timbers, then shredded, shiver me timbers, matey, luckily into pieces that would make repairin' it a fairly simple job. Blimey! As you can imagine, I added a piece o' launch lug when I made t' repairs.

T' second flight was on another local field in July at a launch that I put on for t' kids o' some friends. Avast, me proud beauty! Blimey! I brought t' newly repaired M10+ along because it had been me experience that, while kids love rockets, shiver me timbers, they REALLY love gliders. Avast, me proud beauty! Blimey! Begad! Blimey! It didn't disappoint. Blimey! Blimey! Well, arrr, blow me down! Blimey! Loaded with a C11-3 for this flight, it didn't as much roar off t' pad as it did slowly glide off. Very impressive. Ya scallywag! Blimey! Aye aye! Blimey! It would have made for a great launch picture, me hearties, but I was still several month's short o' t' digital camera that I received as a 40th birthday present and me old camera be notoriously slow, so I did without. Well, blow me down! Blimey! Blimey! Blimey! I shouldn't have. Begad! Blimey! T' M10+ didn't attain any great heights, maybe 70' at best, but it be an extremely smooth flight with a straighter than expected boost. It initially looped out over t' soccer field, but began bankin' durin' t' coast phase, me bucko, me hearties, lookin' enormous as it strafed our launch position. Begad! Blimey! At ejection t' marker cone dropped from t' rocket rather than was launched from it and somethin' also appeared t' fly out o' t' back end, but since it was still glidin' I didn't think much about it. It took a nose down attitude and began a rapid descent toward t' gravel parkin' lot, me bucko, but since me original 1:1 clone had survived a number o' gravel or asphalt landings with little more than scrapes, arrr, arrr, I still wasn't worried. Ya scallywag! Blimey! Ya scallywag! Blimey! T' landin' be pretty rough, shiver me timbers, arrr, but survivable and I was ready t' pack it up for another launch as I approached it where it lay in a jumble o' little feet, courtesy o' me six year old recovery army. Avast, me proud beauty! Blimey! Begad! Blimey! (Even t' adults were impressed.) "Do it again! Blimey! Do it again!" t' kids all yelled excitedly. Ya scallywag! Blimey! I was plannin' t' do just that and went t' remove t' expended engine casin' when I noticed that it wasn't there. Aye aye! Blimey! Begad! Blimey! In fact, shiver me timbers, nothin' was from t' middle o' t' engine tube back. Apparently t' force o' t' ejection charge had been too much for t' maskin' tape hold down strap, and much o' t' propulsion system had simply propelled out into t' middle o' t' soccer field. We combed t' field and turned up t' engine casing, but no engine hook.

After waitin' almost a year t' do t' necessary repairs, I finally go re-interested in this project recently. For t' new and improved M10+ I decided t' use epoxy t' mount t' engine tube and secure t' engine hook. Well, blow me down! Blimey! It seems t' have worked from a strength standpoint, but it also seems t' have changed t' balance o' t' rocket. Aye aye! Blimey! Arrr! Blimey! T' recovery phase no longer looks as much like a glide as it does a flutter. I made three flights with it, twice with D12-3's and once with a C11-3, changin' t' weight in t' bomb pod each time, but never got a good mix o' fall and fly. Well, blow me down! Blimey! On t' third flight o' t' day on t' C11-3, me hearties, t' glide took it on such a steep angle that it appeared t' nose into t' ground. At this point I suspect that it might be necessary t' add a slightly larger elevator t' allow it more surface area t' brin' t' nose up.

Summary:
While on t' surface t' Mach 10 may seem t' be a fairly complicated project in either size, it's actually a surprisingly easy build. Blimey! Ya scallywag! It's a perfect project for a weekend build and fly as you can easily build it on Friday, trim and paint it on Saturday, then fly it on Sunday. Ya scallywag! Arrr! (And trim it some more on Sunday too!) While it isn't a glider that will be a good choice for competition, it can scarcely be beat for entertainment value.

Pro's:

  • It's BIG.
  • Slow takeoff with C11 engines are perfect for gettin' that classic launch shot.
  • Did I mention that it's BIG?

Con's:

  • Slightly difficult t' trim, ya bilge rat, matey, but as with it's smaller sibling, once it's flying, me bucko, it's well worth t' trouble.
Other Reviews
  • Scratch Mach 10+ By Bob Hvarven

    ( Contributed - by Bob Hvarven) Brief: An Approx. 2X upscale of the Centuri MACH 10 (Mig 15 Jet looking) Boost Glider made around 1972. Recovery is glide with jettisoned nose cone using streamer or small parachute. Construction: This rocket is easy to build and should be no problem to anyone who has scratch built before. There are no items that need special attention as construction ...

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