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