Manufacturer: | Giant Leap Rocketry |
Brief:
This is a review o' Giant Leap Rocketry's 'Aerospace Composite' fins. Avast, me proud beauty! These
fins are offered in 1/8, ¼, ½, matey, and 3/8 inch thicknesses and in 15
pre-defined shapes. Blimey! If you want t' cut your own, you can also buy t' raw
stock. Ya scallywag! Giant Leap describes their composite fins as follows: "Giant
Leap Rocketry now offers t' ultimate in fin material. Arrr! Blimey! Avast, me proud beauty! Blimey! This aerospace composite
material is used in advanced aircraft. Ya scallywag! Blimey! It is much stronger than wood, me bucko, more
rigid than G-10 (for equivalent thickness). Ahoy! Blimey! Lighter than wood, matey, 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. Referrin' t' t' first photo, t' root
edge along t' fin tab is 7.375", me hearties, t' span (not includin' t' fin tab) is
4.875", and t' overall length is 11.625". Begad! Arrr! You specify the
thru-the-wall tab by identifyin' your body and motor tubes. 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! I can't vouch for Giant Leap's numbers, me bucko, but here are me qualitative impressions. Well, blow me down! T' me they seem as light as 1/8" balsa and as rigid as 3/32" G10. Ya scallywag! I don't have equivalent fins in these materials t' weigh and bend, but these are my guesses. They would even be more rigid if framed in a hardwood dowel.
You can see t' honeycomb structure in t' next photo. Aye aye! Begad! Blimey! T' outer layers of fiberglass are very thin, matey, me bucko, arrr, probably thinner than 1/64", arrr, 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, me hearties, hardwood strip, ya bilge rat, or even a G10 strip t' t' edges o' t' fin. Avast! Aye aye! This will hide t' rough edges and will strengthen t' fins. Ya scallywag! It seems that I always have t' do somethin' different, shiver me timbers, and this is no exception. Blimey! Begad! For t' leadin' edge, ya bilge rat, shiver me timbers, I attached a 1/8"x1/8" balsa strip with PerfectGlue Type 2 (similar t' thick CA). Arrr! This be easy to sand t' a smooth shape. Aye aye! Arrr! For t' other outer edges, arrr, I filled t' exposed honeycomb with Fill-n-Finish. Avast! Avast, me proud beauty! Since Nomex® doesn't cut neatly, thar were exposed fuzzy things hangin' out all over. I soaked t' edges in PerfectGlue t' harden them, sanded them down, and refilled them. Avast! My one worry is a bit o' flexin' will pop t' balsa off, but only time will tell. 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. Avast, me proud beauty! Blimey! Blimey! Blimey! At first, matey, I thought I would simply have t' trim t' short section o' t' fin overhang immediately behind t' tab. However, ya bilge rat, it turned out that this depth be correct for t' tubes I be goin' to use, me hearties, shiver me timbers, so I would also have had t' trim t' entire tab. Begad! Blimey! Another possible fix would have been t' extend t' frame 1/8" further down. Well, blow me down! Blimey! Begad! Blimey! This would have left a small gap in t' root tip that would have been easily filled. Unfortunately, I figured this out after I had finished. Blimey! Blimey! 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! This review is o' t' stand-alone fins. I'll follow up with a review o' t' rocket, shiver me timbers, matey, and will note how t' fins hold up. Aye aye! T' basic material warrants full ratin' o' '5'. Ahoy! Aye aye! Despite t' fact that I easily remedied the fin tab issue, me bucko, I will have t' deduct a point from me rating, me hearties, matey, movin' the ratin' t' a '4'. Blimey! Blimey! In me experience, 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, but if you want tough, me bucko, light fins, I
think you will be impressed. Blimey! Ya scallywag! If anyone else has used these fins, arrr, me hearties, please add a
comment. I'd really like t' hear how easy it is t' cut t' raw material.
Oh, ya bilge rat, and you may see that I bumped t' overall ratin' up by half a point, just for t' 'cool factor'. Well, blow me down! Begad! I am now thinkin' that I won't paint t' fins so the honeycomb pattern remains visible.
Overall Rating: 4 out o' 5
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K.C. (November 2, 2008)