tried to build a light weight tub... and failed :(

[Roger Hooks Jr.]

Not what I was reading in.. You stated how much faster.. and to PROVE that "on the water using our toy boats" is completlty another matter.

Grim

This was my original question...

Would a lighter (and I'm guessing it makes for a faster) boat give a guy that much of an edge to pull to the lead if he was unlucky enough to be at the line right at 0 going full speed but the boat on the outside?

So I think it was evident that I was leaning TOWARD the fact that a light boat was faster as I highlighted in parenthesis but just posed the question on whether if it was enough to provide enough edge to pass on the outside with all other variables being equal. That is the whole of my very first question.

Perhaps some gentlemen who make a living off of selling toy, that might have a bit more testing time at their displosal than the rest of us, could dedicate an hour or so at the pond to prove or disprove the effects of lighter versus heavier in a real-world test. If not maybe my friends at myth busters can take it on. I Already worked with them using R/C helicopters to test a theory regarding the precision of rotor blade balancing and th effect it would cause if they were even slightly unbalanced.

 

[Ted buckley]

Not what I was reading in.. You stated how much faster.. and to PROVE that "on the water using our toy boats" is completlty another matter.

Grim

This was my original question...

Would a lighter (and I'm guessing it makes for a faster) boat give a guy that much of an edge to pull to the lead if he was unlucky enough to be at the line right at 0 going full speed but the boat on the outside?

So I think it was evident that I was leaning TOWARD the fact that a light boat was faster as I highlighted in parenthesis but just posed the question on whether if it was enough to provide enough edge to pass on the outside with all other variables being equal. That is the whole of my very first question.

Perhaps some gentlemen who make a living off of selling toy, that might have a bit more testing time at their displosal than the rest of us, could dedicate an hour or so at the pond to prove or disprove the effects of lighter versus heavier in a real-world test. If not maybe my friends at myth busters can take it on. I Already worked with them using R/C helicopters to test a theory regarding the precision of rotor blade balancing and th effect it would cause if they were even slightly unbalanced.

Absolutely No - In my opinion.. If Boat A(Heavier boat) & Boat B(Lighter boat) were both at the line at the same time(Same Mph) - going full speed with Boat b being on the outside, he would have NO advantage over Boat A, because they would both be extended to full speed... Neither one would be going faster than the other. You would only have the advantage if you were not extended to full speed.. Thus; Boat B would have and advantage because he has less energy to expell to get up to speed vs. Boat A.

 

[moparbarn]

in my run off with tim, we hit the line with tim about 5' behind me. i ran lane 1/2 for 5 laps, he ran as tight as he could, without causing a foul on his part. he could do no more than pull even with the rear corner of my boat at the end of the straights. this went on for 5 laps. weight/speed? really don't know. i can weigh my sundowner, & get up with tim to post a weight of his sgx. speed difference prolly was less than 4-5 mph, as he couldn't clear me in a straighaway. btw, my sundowner is running a cmb goldhead TT, set on kill by rod g. B) , pulling a seriously modded 1445 from tru spin props. haven't ever radared it, guessing something in the 60's.....but just a guess.

 

[TomMoorehouse]

Id like my thread back..... I was talking about making a lighter boat. This was not to be a debate on the merits of having a lighter boat....

 

[Grimracer]

Sorry Tom

lol.. Your right..

Roger.. your going to have to do the math to figure it out..

lane one IMPBA is 867' long. lane two is about 17.5 feet longer. You are making (lets call it 10 sec laps).. Your boat weighs in a…….... Im brain just sneezed!

 

[Ted buckley]

Sorry Tom..

 

[Grimracer]

I tried to build a light weight jae tub and failed. Here is what I did:

tub sides are 1/4" light ply with big holes cut in them to make them lighter. Then I skinned it with 1/64" plywood

radio box front bulkhead is 1/8" 3 ply

Transom is 1/16" plywood (was going to double this but have not yet)

front is just foam, no bulkhead.

tub top is 1/64" plywood

tub bottom is 1/32 plywood

No tub nose has been attached yet. It was going to be just balsa.

weight is 225 grams

How can this be improved?

Ideas?

Tom.. how do you know you failed?

improved.. I dont know man.. looks to me like you have a good weight going.. I do however use 1/8" light ply for doublers and formers. Not sure thats going to help all that much tho

Grim

 

[Bill Gibson]

Sorry Tom, i started it, wont happen again..was just messin around!

 

[TomMoorehouse]

I feel like I failed because it was heavier and weaker than the tub I built with my normal methods.

 

[moparbarn]

tom, i'm sorry, too. i dragged it out there as bad as anyone.

 

[Roger Hooks Jr.]

Sorry didn't mean to thread jack you. : )

 

[dwilfong]

Any result on the weight testing.

Would like to see some comparisons of different materials.

David

 

[Ted buckley]

I tried to build a light weight jae tub and failed. Here is what I did:

tub sides are 1/4" light ply with big holes cut in them to make them lighter. Then I skinned it with 1/64" plywood

radio box front bulkhead is 1/8" 3 ply

Transom is 1/16" plywood (was going to double this but have not yet)

front is just foam, no bulkhead.

tub top is 1/64" plywood

tub bottom is 1/32 plywood

No tub nose has been attached yet. It was going to be just balsa.

weight is 225 grams

How can this be improved?

Ideas?

At first I was wondering why this tub only weighed-in @ 225 grams and thought, I wish mine came-in at that weight. That's light!! But I noticed that you don't have the engine railers/tube supports/or any other of the stuff that's permanently installed in the hull,(B4 you weigh it). Mine came-in at nearly double that weight(With all hardware removed/Electronics,and finish attached). 225grams is light - I agree, but where is the Official Weight taking step? Everyone has a different point where they take their weight measurement. Mine, is with all permanent installments (i.e. Engine railers/Tubes/servo mounts(made of wood)/stuffing box w/o the shaft/ and last but not least - the completed finish.. This would be the Total hull without any of the hardware/Electronics & fuel to take you mesurement. Don't get me wrong - Tom, I think your 225grams is a very good weight - even without the rest of that stuff in the hull. I guess, unless we come-up with some sort of new material scraped-up from the 1947 Roswell crash-site, we won't get too much lighter than that.

 

[moparbarn]

my jae .21 tub came in at 434 grams. all mounts (engine & 3 servos), stuffing tube, boom tubes, pushrod seal mounts & strut mount block/extension installed. inside sealed, no finish (too cold here). built as per instructions, no ca, no extra attention paid to saving weight (plenty of epoxy on the joints). all bulkheads & transom pinned.

 

[Ted buckley]

my jae .21 tub came in at 434 grams. all mounts (engine & 3 servos), stuffing tube, boom tubes, pushrod seal mounts & strut mount block/extension installed. inside sealed, no finish (too cold here). built as per instructions, no ca, no extra attention paid to saving weight (plenty of epoxy on the joints). all bulkheads & transom pinned.

434grams - still weigh's 0-lbs. 15.30oz - doesn't it?? You mean to tell me that you have all that stuff in your hull & it weigh's 434grams? You sure your not meaning 1600 grams??

Maybe I'm not reading your post correctly :blink: I don't like using grams - rather oz.'s B)

 

[TCHedOff]

Tom,

Here's one for you:

For foamcored sponsons, only use ply on the inside where the stress occurs... use Monokote for the outer sides - wont even require a sealer.

For the tub, you could probably get away with Monkote sides where the radio box is (just leave a framework of ply to attach to. Could probably use the stuff in other non-strength spots as well. But in in a WOT impact, nothing left to recover!

 

[Ted buckley]

my jae .21 tub came in at 434 grams. all mounts (engine & 3 servos), stuffing tube, boom tubes, pushrod seal mounts & strut mount block/extension installed. inside sealed, no finish (too cold here). built as per instructions, no ca, no extra attention paid to saving weight (plenty of epoxy on the joints). all bulkheads & transom pinned.

434grams - still weigh's 0-lbs. 15.30oz - doesn't it?? You mean to tell me that you have all that stuff in your hull & it weigh's 434grams? You sure your not meaning 1600 grams??

Maybe I'm not reading your post correctly :blink: I don't like using grams - rather oz.'s B)

I think I was reading this incorrectly.. I thought he was including the engine & servos also, Still very good weight for this. Has anyone tried using just plain ole Balsa (Skinned with 1/16 or 1/32 ply)? I bet this would make a light tub - with the regitity needed.. :huh:

 

[LarryConrad]

. Has anyone tried using just plain ole Balsa (Skinned with 1/16 or 1/32 ply)? I bet this would make a light tub - with the regitity needed.. :huh:

Ted,

Read post # 12,17,24,and 32

 

[moparbarn]

my jae .21 tub came in at 434 grams. all mounts (engine & 3 servos), stuffing tube, boom tubes, pushrod seal mounts & strut mount block/extension installed. inside sealed, no finish (too cold here). built as per instructions, no ca, no extra attention paid to saving weight (plenty of epoxy on the joints). all bulkheads & transom pinned.

434grams - still weigh's 0-lbs. 15.30oz - doesn't it?? You mean to tell me that you have all that stuff in your hull & it weigh's 434grams? You sure your not meaning 1600 grams??

Maybe I'm not reading your post correctly :blink: I don't like using grams - rather oz.'s B)

I think I was reading this incorrectly.. I thought he was including the engine & servos also, Still very good weight for this. Has anyone tried using just plain ole Balsa (Skinned with 1/16 or 1/32 ply)? I bet this would make a light tub - with the regitity needed.. :huh:

ted, no engine or servos, just the mounts. the brass tubes for the boom tubes, not the actual boom tubes. i prolly could have been a little clearer.yes, right at 15 1/4 oz. might loose that 1/4 oz., haven't sanded/profiled the nose block yet.

 

[TomMoorehouse]

I started a new tub with just 1/8 light ply sides... ill report when I get further along.