ACME Spitfire Upscale

[g_boxwood]

Dear Gentlemen,

I finally got some decent pictures of what has been put together so far!

I started building it during September 2003 and put it aside 'till now... Basic design consists of:
- a continuos LOC 1.52" MMT that runs inside the whole length of the rocket (as the original);
- three LOC 3.90" BT sections cut to the appropriate angle using enlarged original ACME skins as wrap-up templates;
- TTW fins (more on this later);
- balsa-sheeted tailskirt and conical nosecone.

The attached picture shows that:

EACH BT section is secured to the MMT by 2 centering rings (lower and upper one) that are perpendicular to the BT section itself (and not to the MMT); that solution keeps the CR circular and not elliptical meaning less material (thus less weight) is needed.
Moreover you only need to cant the inner edges of the CR (where it meets the MMT) instead of the whole outside diameter... (where it meets the BT) Hope it is clear !?!?!? Let me know...

Here you see the upper ring of the 2nd BT section...

 

[g_boxwood]

Originally posted by g_boxwood
- TTW fins (more on this later);

Here I am again...

Each fin is sandwiched between two CRs, the aft one being the largest. A mid ring is also employed and it features a half-depth notch that snaps into the corresponding half-depth notch on the fin tab. This arrangement helps aligning the fins and offers additional supports for the balsa sheeting later on.

So, here you can see the three CRs from the business end...

 

[g_boxwood]

... the same 3 rings from above (the upper one is partially hidden by the first BT section)...

 

[sandman]

Giacamo,

What size is your A.C.M.E.?

I cannot tell from the pictures.

sandman

 

[g_boxwood]

... and a close-up of the CR-fin tab notches between fin 1 and 4.

That's all for the moment, hope you enjoyed!!! Will update You as soon as the work progresses !

Ciao,

Giacomo

 

[g_boxwood]

Originally posted by sandman
What size is your A.C.M.E.?

It is 30" tall without the nosecone which I haven't designed yet. Should be about 34-35" overall.

Ciao,

Giacomo

 

[powderburner]

Originally posted by g_boxwood
EACH BT section is secured to the MMT by 2 centering rings (lower and upper one) that are perpendicular to the BT section itself (and not to the MMT); that solution keeps the CR circular and not elliptical meaning less material (thus less weight) is needed.

That is truly inspired. Simple, easy, and I'll bet it works great! The weight thing probably does not make much difference, but all the rest is very well thought out. I am gonna have to copy that on the next original-size Spit that I build.

And welcome to TRF! Anyone who shows up with good ideas like this is extremely welcome!

 

[g_boxwood]

Originally posted by powderburner
I am gonna have to copy that on the next original-size Spit that I build.

And welcome to TRF!

Thank You powderburner! I think that this solution is not so different from that of the original Spitfire... I neither possess the original nor read the reviews carefully but it seemed pretty close to me... anyway glad You liked it. BTW each CR is 3mm birch ply (slightly less than 1/8") as well as the fins.

This evening I filleted the fins and added a layer of 6 oz. glass let's say 'from root to root (and across the MMT)'; here you can see the cloth prior to wetting it with epoxy...

 

[g_boxwood]

... and after,

Ciao,

Giacomo

 

[g_boxwood]

Good Evening (my time),

I resumed building...

After having glassed the fins root-to-root I left the lower parts of the ACME and concentrated on the upper airframe; I still needed to epoxy the last section (3rd) of BT in place. Prior to that I wanted to carefully plan the 'chute attachment.

I laminated three 6mm (1/4") birch ply discs, canted the edges of the cylinder and epoxied it in place against the MMT; I then trimmed the MMT itself and placed the last CR (1/4" this time) over the cylinder; it's a lot easier if You consider the attached picture.

 

[g_boxwood]

I finally placed a left-over canted disc over the CR aligning it with the cylinder below, I gave a generous epoxy+chopped fibers fillet and drilled the hole for the screw-eye; this way the screw eye was deeper attached to both the two last CRs (that have opposite angles) AND it was aligned with the MMT (and with gravity itself BTW). Again, see picture.

The last BT section was then epoxied and the last check took place: the shock cord must exit the BT without resting against the canted BT edge; done (it is close but the tube will be glassed).

I will now dedicate some time to rail button location and backing, motor retaining (I got the polished alu Rowes coned retainer and it looks great) and I'll be ready to panel the tailskirt and glass the entire model.

the nosecone will be the very last thing.

Ciao,

Giacomo

 

[jflis]

You certainly have *my* curiosity piqued can't wait for some overall shots and the finishing!

 

[g_boxwood]

...seems like I have to put this project aside form time to time...

After my L2 Big Nuke I can now concentrate on completing this one!

Basically I added the balsa skirt panels and the fin fillets (masked 2-part automotive putty) and started the tip-to-tip glassing to reinforce the balsa-sheeted skirt. It will take four days for the four tip-to-tip, one more day for the aft centering ring and the last one for the body tube itself... then... the nosecone.

May someone help here please? I don't own a original A.C.M.E. and I would prefer not to form the n/c form the enlarged template because I'll probably get it not too precise; what I mostly need is n/c specs such as base diameter, height and things like that. Thanks in advance.

In the attached pic you can see the first 6oz. layer going on...

 

[g_boxwood]

Here is another view from above.

Now what you guys think this bird would love to fly with? I was thinking about a Blackjack reload (we cannot have Cesaroni here) to mate the crooked look and was oriented toward a powerful one to help with stability issues (unknown) such as the I195J (38/600). Any suggestion and/or preference?

One last thing: does anyone know where is the CP approximately located (on the original version as well)?

 

[DPatell]

Too cool. Everything you do is neat. I envy you!!!


Very SEXY look to it, I must say

 

[Adam Selene]

Originally posted by g_boxwood
Here is another view from above.

Now what you guys think this bird would love to fly with? I was thinking about a Blackjack reload (we cannot have Cesaroni here) to mate the crooked look and was oriented toward a powerful one to help with stability issues (unknown) such as the I195J (38/600). Any suggestion and/or preference?

One last thing: does anyone know where is the CP approximately located (on the original version as well)?

any redline you could get ahold of would look cool!

i HOPE that jim could give you the CP of the original!

i'd love to see this fly!

 

[Adam Selene]

Originally posted by g_boxwood
May someone help here please? I don't own a original A.C.M.E. and I would prefer not to form the n/c form the enlarged template because I'll probably get it not too precise; what I mostly need is n/c specs such as base diameter, height and things like that. Thanks in advance.

if you still need figures, this might be just the excuse i need to take mine out of the bag and build it!

what units would you like the measurements in? i've got a mm tape around here somwhere.
or again i hope jim would know
but let me know if i can help.
-chuck

 

[Adam Selene]

btw- very cool of you to build an upscale of a kit you don't have. i don't think i could do that!

 

[g_boxwood]

Originally posted by DPatell
Too cool. Everything you do is neat. I envy you!!!
Very SEXY look to it, I must say

Thank you Dan !!! I'm glad someone else find what I do and HOW I do it neat... I'm always a lot more critic with what I do and the way I do it !!!

Remember I owe you a L850 flight (IF everything goes fine ahead of it ).

 

[g_boxwood]

Originally posted by Adam Selene
if you still need figures, this might be just the excuse i need to take mine out of the bag and build it!
what units would you like the measurements in? i've got a mm tape around here somwhere.
or again i hope jim would know
but let me know if i can help.
-chuck

Of course I need your help Adam: basically all you can tell me about a FINISHED nosecone would help me a lot ! That includes base diameter, height, wheter or not the nosecone is symmetric...
if you can and if it doesn't take that much time !

Thank you,

 

[g_boxwood]

Originally posted by Adam Selene
btw- very cool of you to build an upscale of a kit you don't have. i don't think i could do that!

Yes you could! It happened with the Deuce's Wild (that I'm perfectioning at the time) and now with the Spitfire and that's because when dealing with this unique designs you have to develop different solutions from the originals thus allowing you to design rather than copying and enlarging! In the case of the Spit moreover Fliskits offered a great opportunity to make all the necessary body tube sections and fin patterns providing the original templates on their site (and that helped A LOT!!!).

 

[Adam Selene]

I'm afraid i won't be able to help with the measurements after all. i leave on a long road trip monday morning and i will not have time to build it before than. too much to do. but i'm sure jim will be happy to help.

 

[jflis]

I will have to do some digging myself to get the CP... I'm currently buried under a mountain of mail, orders, kitting and cleaning after an 11 day trip...

I'll see what I can find

 

[scm86]

Giacamo,

glad to hear someone else is upscaling the acme. Im doin an upscale too, but one step bigger, using a 54mm central tube and a 5.375" body tube. Everything was made using the wraps and templates from the original acme.

I dont have my website upadated with the pictures yet, but those who are interested can check out the images directory of my page where you can click on the names and get the pics https://www.mlinks.net/~scottm/images/

If people could post the CG of their small acmes im sure it would benifit us both, so we can see where we need to have ours at, as im sure rocksim wont take the acme...

Scott McNeely

 

[Adam Selene]

hey jim, how did you figure out the cp of the acme? or did you just do a string test?

 

[jflis]

Originally posted by Adam Selene
hey jim, how did you figure out the cp of the acme? or did you just do a string test?

well, as I commented in the thread beep! beep! , I just uploaded the design into FlisSIM V3.0, as shown in the attached pix...

 

[g_boxwood]

Hi guys,

I went with all the 4 tip-to-tip reinforcements these last few days (one per day keeps the doctor away...) while today I glassed the body tube THE Carl's way ! So far it has been the strangest glassing I did on a rocket but Carl's tech is flawless !!!

Here are some pics (hope I don't bother too much):

- Glassed fincan, spirals filled and everything cleaned up and ready to go

 

[g_boxwood]

- Cloth secured to the airframe centerline using medium CA

 

[g_boxwood]

- Cloth edge trimmed after CA has cured

 

[g_boxwood]

- Cloth wrapped up and tightened well around the tube; edge secured with CA