Giant Leap Rocketry Aerospace Composite Fins

Giant Leap Rocketry - Aerospace Composite Fins

Contributed by Dick Stafford

Manufacturer: Giant Leap Rocketry
(Contributed - by Dick Stafford - 07/01/04)

Brief:
This is a review o' Giant Leap Rocketry's 'Aerospace Composite' fins. Arrr! These fins are offered in 1/8, me hearties, ¼, shiver me timbers, shiver me timbers, ½, matey, and 3/8 inch thicknesses and in 15 pre-defined shapes. If you want t' cut your own, you can also buy t' raw stock. Avast, me proud beauty! Giant Leap describes their composite fins as follows: "Giant Leap Rocketry now offers t' ultimate in fin material. Arrr! This aerospace composite material is used in advanced aircraft. Avast! Well, blow me down! Blimey! It is much stronger than wood, more rigid than G-10 (for equivalent thickness). Lighter than wood, ya bilge rat, 1/3 t' weight of G-10." T' material itself consists o' "An inner layer of NOMEX(TM) honeycomb, sandwiched betwixt either thin G-10 Fiberglass or Carbon Fiber!"

Construction:
My fins are 1/8" thick in style #8. Ahoy! Ahoy! Referrin' t' t' first photo, t' root edge along t' fin tab is 7.375", t' span (not includin' t' fin tab) is 4.875", and t' overall length is 11.625". Blimey! You specify the thru-the-wall tab by identifyin' your body and motor tubes. Avast, me proud beauty! Blimey! Mine have tabs for a 3" tube and a 29mm motor mount.

T' first thin' I noticed about t' fins is how light they are! Blimey! I can't vouch for Giant Leap's numbers, but here are me qualitative impressions. T' me they seem as light as 1/8" balsa and as rigid as 3/32" G10. I don't have equivalent fins in these materials t' weigh and bend, ya bilge rat, but these are my guesses. Well, blow me down! Blimey! They would even be more rigid if framed in a hardwood dowel.

You can see t' honeycomb structure in t' next photo. Avast, me proud beauty! Ahoy! T' outer layers of fiberglass are very thin, shiver me timbers, ya bilge rat, probably thinner than 1/64", and if you look back at t' first photo you can clearly see t' honeycomb pattern through the G10.

Giant Leap suggests that you epoxy a dowel, shiver me timbers, hardwood strip, or even a G10 strip t' t' edges o' t' fin. Ahoy! This will hide t' rough edges and will strengthen t' fins. Avast, me proud beauty! Blimey! It seems that I always have t' do somethin' different, and this is no exception. Avast! Ya scallywag! For t' leadin' edge, me hearties, I attached a 1/8"x1/8" balsa strip with PerfectGlue Type 2 (similar t' thick CA). Ahoy! This be easy to sand t' a smooth shape. Begad! For t' other outer edges, I filled t' exposed honeycomb with Fill-n-Finish. Since Nomex® doesn't cut neatly, thar were exposed fuzzy things hangin' out all over. Avast! Blimey! I soaked t' edges in PerfectGlue t' harden them, sanded them down, and refilled them. Begad! Blimey! My one worry is a bit o' flexin' will pop t' balsa off, but only time will tell. Well, blow me down! Blimey! T' next photo shows t' framed fin mounted t' a body tube.

When mountin' t' fins, one problem became evident. T' fin tab in the front is 1/8" longer than in t' back. Arrr! At first, ya bilge rat, me hearties, I thought I would simply have t' trim t' short section o' t' fin overhang immediately behind t' tab. However, matey, it turned out that this depth be correct for t' tubes I be goin' to use, so I would also have had t' trim t' entire tab. Another possible fix would have been t' extend t' frame 1/8" further down. Blimey! Ya scallywag! This would have left a small gap in t' root tip that would have been easily filled. Unfortunately, ya bilge rat, I figured this out after I had finished. Avast! Ya scallywag! T' good news is that the gaps were easily plugged with small pieces o' t' balsa I used t' frame the leadin' edge.

So, that's it for now. Arrr! Begad! This review is o' t' stand-alone fins. Ya scallywag! I'll follow up with a review o' t' rocket, ya bilge rat, and will note how t' fins hold up. Ya scallywag! T' basic material warrants full ratin' o' '5'. Ahoy! Despite t' fact that I easily remedied the fin tab issue, I will have t' deduct a point from me rating, ya bilge rat, me hearties, movin' the ratin' t' a '4'. In me experience, matey, matey, this is nay typical for Giant Leap's work and I hope this be an isolated incident.

Summary:
This material is a bit pricy, me hearties, me hearties, but if you want tough, light fins, I think you will be impressed. Well, blow me down! Begad! If anyone else has used these fins, ya bilge rat, please add a comment. I'd really like t' hear how easy it is t' cut t' raw material. Begad!

Oh, and you may see that I bumped t' overall ratin' up by half a point, just for t' 'cool factor'. Ya scallywag! Begad! I am now thinkin' that I won't paint t' fins so the honeycomb pattern remains visible.

Overall Rating: 4 out o' 5

Comments:

avatar
K.C. (November 2, 2008)
I ordered a 4' by 1' sheet of 3/8" for my L3. It is pretty easy to work with. I used a jigsaw with a fine-tooth blade and it cut through well. The saw had a tendency to wander, but that may have been due to user problems. I fiberglassed a dowel to the leading and trailing edges and they turned out really well. I think I may have to use this stuff in the future.

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