Dumas Drag N' Fly Hydros (20,40,60 sizes)

[jetpack]

Without going through the rulebooks, can anyone tell me which are currently legal and what class these would fit into? I am hoping the older crowd will know off the bat.

I'm building them for sport but if there's a chance to jump into an organized race, I would like to be able to join in without any technical snags concerning the hull.

These will all be built as inboard versions. All will have the spade front end, no pickle.

 

[ALLAN YUEN]

Without going through the rulebooks, can anyone tell me which are currently legal and what class these would fit into? I am hoping the older crowd will know off the bat.

I'm building them for sport but if there's a chance to jump into an organized race, I would like to be able to join in without any technical snags concerning the hull.

These will all be built as inboard versions. All will have the spade front end, no pickle.

Good Point Question :unsure: show picture?

 

[larcor69]

the drag-n-fly 40 would make a good sport 20 with some sponson mods in IMPBA with rear mounted strut, you will have to improvize your own radio box as far forward as you could, to get some extra weight up front the center of gravity need's to be at about 1/2" behind the rear of the sponson's, would be a fast hull, the 60 size same but a 45 size hull for a sport 40!! old school hull's but can be made to work!!

 

[Bill Gibson]

Ive got a Dragonfly 20 kit and i think that for it to be legal to run in sport 20,per NAMBA rules, id have to stretch it out a coupla inches, but it would still be perfectly legal to run in 20 hydro..though it would get smoked! Also, i would think that with todays modern powerful engines and the spade bows on these boats, you might have a hard time keepin em on the water! Not tryin to discourage you as they are cool old boats...I thought about buildin mine and sticking a brand new old style K&B 3.5 IB that i have along with my first radio...a 1979 2 stick brown box Futaba with S-7 servos that still works as good as the day i got it! How many of you old folks remember that rig??

 

[Jerry Dunlap]

Ive got a Dragonfly 20 kit and i think that for it to be legal to run in sport 20,per NAMBA rules, id have to stretch it out a coupla inches, but it would still be perfectly legal to run in 20 hydro..though it would get smoked! Also, i would think that with todays modern powerful engines and the spade bows on these boats, you might have a hard time keepin em on the water! Not tryin to discourage you as they are cool old boats...I thought about buildin mine and sticking a brand new old style K&B 3.5 IB that i have along with my first radio...a 1979 2 stick brown box Futaba with S-7 servos that still works as good as the day i got it! How many of you old folks remember that rig??

I had one of those. How many ran a model boat using a reed radio system? We're talking 1965 here, folks.

I raced a DragN'Fli 40 in 40 Hydro and a DragN'Fli 60 in 60 Hydro back in the late 60s/early 70s. Had a K&B 40 Torpedo in the 40 boat and a Rossi 60 in the bigger boat. The guy who designed the DragN'Flies, Frank Ward, lived in Seattle. He also designed the Wardcraft Deep Vees. Ah, back in the day.

JD

 

[Tom Foley]

Ive got a Dragonfly 20 kit and i think that for it to be legal to run in sport 20,per NAMBA rules, id have to stretch it out a coupla inches, but it would still be perfectly legal to run in 20 hydro..though it would get smoked! Also, i would think that with todays modern powerful engines and the spade bows on these boats, you might have a hard time keepin em on the water! Not tryin to discourage you as they are cool old boats...I thought about buildin mine and sticking a brand new old style K&B 3.5 IB that i have along with my first radio...a 1979 2 stick brown box Futaba with S-7 servos that still works as good as the day i got it! How many of you old folks remember that rig??

I've got some gears for those S - 7 's if you need them !! Drag n Fly 40 with HB 61 , my first boat in 1981 . Got a new 60 kit in the box saving it for when I have time ...wait ...that will never happen !!

 

[larcor69]

I had a Miss unlimited with a OPS .29 rear exh. my futaba radio brown box with the wheel in the center and light switch type throttle on the right top side, because of that I still steer with my left hand today..lol

 

[jetpack]

Good Point Question

show picture?

Hi Allan, Here is a couple of the best that I've been able to gather of the hulls made by Dumas for their advertisements:

 

[jetpack]

the drag-n-fly 40 would make a good sport 20 with some sponson mods in IMPBA with rear mounted strut, you will have to improvize your own radio box as far forward as you could, to get some extra weight up front the center of gravity need's to be at about 1/2" behind the rear of the sponson's, would be a fast hull, the 60 size same but a 45 size hull for a sport 40!! old school hull's but can be made to work!!

Hi larcor69, here's pictures of something I think you already have a handle on. It's a heavily modded Dragon. I would have to check out the hull lengths to the book, I'm thinking the 40 might be too long for the 20 class? Either way I think you might be right about getting them to work with todays.

I might be wrong but I think the rear shoes are not allowed in any of the classes these could be dropped into.

The sponson mods look great on this one, definetly a lot lower ride over stock. The air dumps through the deck is something I think could be worked into any of the classes.

As far as the drive is concerned, I'll be setting them up with the drive dog to the transom line, at this point at least.

The radio box/balance issue I think I might try going with a rail system between the cockpit sides using small angle each side to form a shelf for a sliding radio box with mounting tabs.

I've also played with the thought of doing this with the engine also, using a plate mount.

Using these two adjustments, three if you want to shuffle the tank, a pretty decent system could be used to test one out. The cockpit sides are parallel most of the way back until you reach the last couple of formers where it tucks in a small amount.

 

[jetpack]

Ive got a Dragonfly 20 kit and i think that for it to be legal to run in sport 20,per NAMBA rules, id have to stretch it out a coupla inches, but it would still be perfectly legal to run in 20 hydro..though it would get smoked!

Also, i would think that with todays modern powerful engines and the spade bows on these boats, you might have a hard time keepin em on the water! Not tryin to discourage you as they are cool old boats...I thought about buildin mine and sticking a brand new old style K&B 3.5 IB that i have along with my first radio...a 1979 2 stick brown box Futaba with S-7 servos that still works as good as the day i got it! How many of you old folks remember that rig??

Hi Bill, Thanks for the thoughts on length. Running in 20 hydro if I'm right, it would mean I would be up against riggers. Forget that, unless it's a total wipe-out session, I'll agree. Maybe a ski ramp on back to help the other rigs get past. Now that would be fun.

You're old radio sounds nice. I just started being interested in older radios myself and bought a couple old two and three channel Cox/Sanwa boxes for my 1/2A planes. They go for a princely sum of $10 or so on fleabay and the thought is to convert them over to a new FM systems inside.

My dragon trio will have a matching style of Webra's. Well, almost if you look close enough. The rear intake is a ringed engine and was manufactured later with the aero head and the shrunk jacket. I haven't found the style with the head button with head clamp yet like the other two.

Pictured is starting on the left the 20, then 40 and 61. The top engine is a Webra 60 Blackhead series that is headed for a try in a Dumas U-71 AVL 40.

 

[jetpack]

I had one of those. How many ran a model boat using a reed radio system? We're talking 1965 here, folks.

I raced a DragN'Fli 40 in 40 Hydro and a DragN'Fli 60 in 60 Hydro back in the late 60s/early 70s. Had a K&B 40 Torpedo in the 40 boat and a Rossi 60 in the bigger boat. The guy who designed the DragN'Flies, Frank Ward, lived in Seattle. He also designed the Wardcraft Deep Vees. Ah, back in the day.

JD

Reed radios. Aren't those the kind that you carry to listen to as you pick the weeds and reeds out of your prop or is that just some primative form to avoid rock climbing with engine cases.

You had mentioned Frank Ward. I have to wonder or ask if the record-setting with this design of his, was actually taken by him? What size captured it?

I tried to trace this hull back to it's origins and came up with it looking very much like the full-scale cabover designs of Ed Karelsen of Washington. It was raced as the Hilton Hyperlube sponsorship in it's later life. Quite a large open cockpit kneeler. One big transom rider for sure.

I would like to see a pic of one of those Wardcraft's. Were they wood built? I have only one plan for a mono being a Norco Eaglet. Another old school hull but pretty neat.

 

[jetpack]

Drag n Fly 40 with HB 61 , my first boat in 1981 . Got a new 60 kit in the box saving it for when I have time ...wait ...that will never happen !!

I think those HB's are built pretty similar to those Webra's I was showing. Mecoa still carries those engines, and wondered how it would do in a comparison.

I know how you feel about having the time. With me, whatever kits I won't be able to build that I still have around I'll make into retirement kindling next to the fireplace and relax in the rocker with the best jug of 40% cognac.

 

[jetpack]

I had a Miss unlimited with a OPS .29 rear exh. my futaba radio brown box with the wheel in the center and light switch type throttle on the right top side, because of that I still steer with my left hand today..lol

Isn't or wasn't there a steering wheel radio where you could switch steering from right to left? I can't remember for sure. I'm suprised there isn't more radios with that ability and designed with this ergo feature Cox had on their pistol grip way back.

 

[larcor69]

Oh, yea, the Airtronic's M8/11, Futaba 3PK/4PK, and the newer Specktrum radio's all switch to left hand use, looking at that 20, the sponson ride pad's look great, and yes you would have to get rid of the rear ride pad's, Look's like a nice vintage build, Cool, I still have one of my old Dumas sport 21 Mono hull almost fire wood after 30 year's..lol, I also have a vintage Tamiya Super Champ and a 1985 RC10!! I would love to get ahold of that old radio I first had, the Brown box with the wheel in the middle!!

 

[Mike Hughes]

The Super Champ takes me back in the day when I first started to race cars. 13 yrs old. I think I still have a couple of the box radio around here somewhere. Throttle was a lever on the side of the box. Super Champ is long gone. It kept getting beat by the RC10. I remember having to save up my money to buy a RC car. I think I paid 160 or so for my first Super Champ.

Mike

 

[Daniel's Racing]

Ive got a Dragonfly 20 kit and i think that for it to be legal to run in sport 20,per NAMBA rules, id have to stretch it out a coupla inches, but it would still be perfectly legal to run in 20 hydro..though it would get smoked! Also, i would think that with todays modern powerful engines and the spade bows on these boats, you might have a hard time keepin em on the water! Not tryin to discourage you as they are cool old boats...I thought about buildin mine and sticking a brand new old style K&B 3.5 IB that i have along with my first radio...a 1979 2 stick brown box Futaba with S-7 servos that still works as good as the day i got it! How many of you old folks remember that rig??

That is going back. S-7's the waterproof servos, hard to remember those were the beige colored ones twin to the S-29's. Remember those old Dumas Dragonfly's too and the Wing Ding's memories of good times. Build it and have fun.

 

[Bill Gibson]

Ive got a Dragonfly 20 kit and i think that for it to be legal to run in sport 20,per NAMBA rules, id have to stretch it out a coupla inches, but it would still be perfectly legal to run in 20 hydro..though it would get smoked!

Also, i would think that with todays modern powerful engines and the spade bows on these boats, you might have a hard time keepin em on the water! Not tryin to discourage you as they are cool old boats...I thought about buildin mine and sticking a brand new old style K&B 3.5 IB that i have along with my first radio...a 1979 2 stick brown box Futaba with S-7 servos that still works as good as the day i got it! How many of you old folks remember that rig??

Hi Bill, Thanks for the thoughts on length. Running in 20 hydro if I'm right, it would mean I would be up against riggers. Forget that, unless it's a total wipe-out session, I'll agree. Maybe a ski ramp on back to help the other rigs get past. Now that would be fun.

You're old radio sounds nice. I just started being interested in older radios myself and bought a couple old two and three channel Cox/Sanwa boxes for my 1/2A planes. They go for a princely sum of $10 or so on fleabay and the thought is to convert them over to a new FM systems inside.

My dragon trio will have a matching style of Webra's. Well, almost if you look close enough. The rear intake is a ringed engine and was manufactured later with the aero head and the shrunk jacket. I haven't found the style with the head button with head clamp yet like the other two.

Pictured is starting on the left the 20, then 40 and 61. The top engine is a Webra 60 Blackhead series that is headed for a try in a Dumas U-71 AVL 40.

Jetpack...WOW! i LOVE old boats, engines and radios! I ran an old 40 size Dumas PaynPak with a 40 Webra Marine and that motor ran GREAT! It started and idled like an airplane motor...that thing was so easy to start that i could use a shoe string to start it! Just rock the flywheel a coupla times, then pop it! Also ran a U-71 in sport 40 back in the early eightys! Had an old K&B 7.5 disk rotor in it..the boat was a rocket in the straights, but you had to kinda tiptoe it in the turns because it was so narrow it would hook if you pushed it too hard! Try not to overpower it! Please keep me posted on your progress with any of your old stuff and show PICS! COOL STUFF!

 

[Bill Gibson]

Ive got a Dragonfly 20 kit and i think that for it to be legal to run in sport 20,per NAMBA rules, id have to stretch it out a coupla inches, but it would still be perfectly legal to run in 20 hydro..though it would get smoked! Also, i would think that with todays modern powerful engines and the spade bows on these boats, you might have a hard time keepin em on the water! Not tryin to discourage you as they are cool old boats...I thought about buildin mine and sticking a brand new old style K&B 3.5 IB that i have along with my first radio...a 1979 2 stick brown box Futaba with S-7 servos that still works as good as the day i got it! How many of you old folks remember that rig??

That is going back. S-7's the waterproof servos, hard to remember those were the beige colored ones twin to the S-29's. Remember those old Dumas Dragonfly's too and the Wing Ding's memories of good times. Build it and have fun.

Still using s-29s in a coupla boats..great old servos..the only thing was that they were just a LITTLE larger than standard servos so if you wanted to put an s-29 where a standard size servo was..you had to do a little hackin!!Do you remember switching the wires on the servo pot to reverse the servo???Man im gettin old!!

 

[carlnoki]

just a couple words on couple of the Webras you are going to be running.

The 60 Black Heads carb can handle nitro up to around 15-20%/

Beyond that and you MUST take the spray bar section out of it and open up the grooved

section that handles the low speed PLUS open up the actual hole (facing the inside of the carb)

so that the motor will not run lean and that you can actually richen both the high and low speed

needles.

Remember that on that motor, the Dynamix carbs low speed needle works BASS AKWARDS from a standard carb.

screw the needle in and it gets richer , screw it out and it gets leaner on the idle.

this is a characteristic of that carb. and the low speed needle REALLY effected the high speed one.

The Speed 61 rear intake side exhaust motor has only one minor problem.

take the rear gasket OUT and seal that area with a thin film of high temp silicone.

the Disk is not hardened as well as it should be and the drive pin from the crank will

wallow out the disks driven slot area. (or you can measure the distance from teh crank pin

to the disk face and have material from the rear cover removed so that the drive pin sits

deeper into the disks driven slot area.

In case you haven't guessed it by now, I used to run those motors when Circus Hobbies

was in business way back when.

I also used to use O.S. Reed radios when i started in R/C.

Carl

 

[jetpack]

Hi Carl, seems you've been down the Dynamix road before. Thanks for the heads up on that!

The Webra's I have, I've been able to find both the standard carb and the Dynamix carb to try out. All are properly sized for the engine per factory specs. The standard carb that is on the .61 is past their "standard" variety with it having the third channel needle adjustment. I've also gathered Perry VP-30 fuel pumps for when I try out the Dynamix carbs. They don't draw on their own very well and work best by being regulated.

One question I do have which hasn't been answered very well for me in the past is when the fuel mixture tube is re-installed into the dynamix carb, what location should the V groove have? My best guess is to have the top of the groove should be set up to be square with the bore, leaving the V just below centerline on rotation.

Would you or anyone else have any clues on this? It is a factory setting which once the spray bar is removed from the throttle plate assembly, it is lost. I'm thinking of setting up some type of primative flow bench to try and set the spray bar for the best draw.

This aspect of rebuilding these motors is about the only one I'm left guessing about. There was no way for me to actually see into the bore when they were taken apart to get some type of idea about the exact position of the groove. Pointing it too far up and you'll get positive pressure back through the fuel line because of it acting as an air scoop. Pointing it too far down and you're getting poor atomization and lousy transitions.

I would like to be able to set them without having to flow the fuel draw, mainly because I'm not even sure about if that's the right way to do it, so I'm looking for clues past my theory on this.