RE: The Unofficial all things Jet drive thread
The reason that you see a lot of frustration in the airboat territory is because it is mostly uncharted territory. There is a setup/hull that is optimised for them, and the people who usualy build them are sucessful. Things stop working when you stray from the beaten path. Then again, that is where innovation occurs. I built my first two airboats on my own accord... no plans or prototypes reviewed. They were flawed designs, one of which flipped on the first turn and burned the electronics (they were cheap, non hobby-grade components). The second one was a catamaran type of hull, and due to it being more of a displacement hull it didnt get on plane well. My third one was built from modified plans I found online, and is one of my most successful boats to date. A tunnel for the jet would be a nice idea, gives the jet a "fresh" flow of water and should lessen cavitaion. Good luck, I have had an idea similar in my head, however I don't have the time to build it with school and sports.
Posted on: 10/3/2009 8:56 PM by Author "ISIRC10" in the forum "Speed - Electric"
http://www.rcuniverse.com/forum/fb.asp?m=9144394

RE: making my first airboat, please help
is that throw or torque? If it is throw then you can extend the servo horn and make it longer, creating more throw. at most you would probably need 45* of throw from neutral both ways, correct me if i'm wrong. Have you thought of enlarging the surface area of the rudders? Just puting some ideas out there. Anyways, you can try with two servos, I guess it can't hurt?
Posted on: 9/1/2009 9:03 PM by Author "ISIRC10" in the forum "RC Airboats"
http://www.rcuniverse.com/forum/fb.asp?m=9062897

RE: The Unofficial all things Jet drive thread
Well while you guys were messing around with your impellers (and the awesome jig used to make them) I finished the partial rebuild of my jet boat, and decided to spruce up the paint a bit. After spending an hour masking and drawing the patterns, I sprayed on a gloss blue. Then I figured I would try a fade. Of course this wasn't going to be very professional as I was using spray cans, but I took the risk and sprayed the front with some gloss white. I think it turned out nice, and after applying some decals she was ready for testing again. Then it started pouring outside. I just love how the weather cooperates with you when you need to do something fun, and not when you have to mow the lawn or do yard work.... Oh well, I guess I will do some tests during the weeked and post a vid/results EDIT: sorry, the pics are uploading huge, this hasn't happened before, so I will upload them to another server. i215.photobucket.com/albums/cc21/ISIRC10/P1030157.jpg i215.photobucket.com/albums/cc21/ISIRC10/P1030159.jpg i215.photobucket.com/albums/cc21/ISIRC10/P1030160.jpg i215.photobucket.com/albums/cc21/ISIRC10/P1030161.jpg i215.photobucket.com/albums/cc21/ISIRC10/P1030162.jpg
Posted on: 9/1/2009 6:29 PM by Author "ISIRC10" in the forum "Speed - Electric"
http://www.rcuniverse.com/forum/fb.asp?m=9062526

RE: making my first airboat, please help
[quote]ORIGINAL: kieran3008 480 brushed motor out an old plane with a pusher prop, i want it probably 25inches long by about 15 wide [/quote] Man, I don't know about you, but I am not too confident that you will have enough thrust... That hull is fairly large, even for a 550 brushed motor... I would have gone 18" by 10" or something around there... Then again, I have only one successful airboat and it is running a BL - Lipo combo after a short spell with the brushed 550 proved to be very slow. Just my 2c
Posted on: 9/1/2009 6:08 PM by Author "ISIRC10" in the forum "RC Airboats"
http://www.rcuniverse.com/forum/fb.asp?m=9062493

RE: Ducted fan build
well, I think that calls for a test then! make a simple outrigger out of foam and mount the DF plus electronics (in a tupperware container, nothing fancy) and let her rip! at least thats what I would do... then I would make a hull from that and make it fancy and all... BTW, this may be a bit off topic, but your paintin skills have got me envious.... so I took a major risk yesterday. I risked messing up a perfect flat black paintjob on my jetboat in order to acheive a three color scheme... this was the first time I used more than two colors on a project... I am still stuck with spray cans, but this is how it turned out - blue painters tape and some careful spraying can come a long way. I am very proud of my first "true" paint job! BTW, this is also the first time I tried to do a fade. Not too bad me thinks, it could have been better but I like it anyways. Thanks for the inspiration, thats what pushed me to experiment!
Posted on: 8/30/2009 9:50 PM by Author "ISIRC10" in the forum "RC Airboats"
http://www.rcuniverse.com/forum/fb.asp?m=9057498

RE: Unofficial
Okay, thanks! The boat I am testing right now is 15" long 6" wide 2.5" tall you may have seen it on the other thread, I probably won't post any pics of it on here as this is a NDQ thread. However, I think that it is very similar to the NDQ so it should be able to hold its own. Only one way to find out tho.
Posted on: 8/30/2009 9:35 PM by Author "ISIRC10" in the forum "Speed - Electric"
http://www.rcuniverse.com/forum/fb.asp?m=9057464

RE: Unofficial
Guys, I have a question - What are the specs of the hulls? I have a hull that I am testing currently that I would like to compare with these. If I could get the measurements, it would be immensly helpful in the comparisons. I think I have a winning combination but I want to see how it holds up to these boats. Thanks, and sorry if someone allready posted the specs and I missed them!
Posted on: 8/30/2009 9:05 PM by Author "ISIRC10" in the forum "Speed - Electric"
http://www.rcuniverse.com/forum/fb.asp?m=9057402

RE: Ducted fan build
Strakes they are called me thinks...?
Posted on: 8/26/2009 7:25 PM by Author "ISIRC10" in the forum "RC Airboats"
http://www.rcuniverse.com/forum/fb.asp?m=9047673

RE: Ducted fan build
srw1960 - don't give up! My first airboat was a pretty unique design that didn't work at all. She was just too heavy and my electronics couldn't handle it. That was a huge dissapointment for me. I have a few questions about your boat... how heavy is it ready to run? I am hoping it is under three pounds - that is what experience tells me is a limit for the electronics (mine at least) Another thing - what was the water doing in your elec. box? did it get through the seal on the top or the cooling lines for the esc? If the fan fails, stick a 8x6 prop on the bl motor (run it off a lower voltage to avoid cooking another esc) and use that... Best of luck, hopefuly it's just an issue of thrust vectoring.
Posted on: 8/23/2009 2:33 PM by Author "ISIRC10" in the forum "RC Airboats"
http://www.rcuniverse.com/forum/fb.asp?m=9038062

RE: The Unofficial all things Jet drive thread
Well, while you guys are experimenting with your boats, I have been doing so with my own. ...not realy though ;) I just spent a few days picking out old bits of epoxy and jb weld and re-sealing the jet drive. After tesing it in the tub, I realised that I never measured the thrust of my setup. That was what I did next, and it was a bit tricky. I attached a scale to the boat using a harness that fit over the bow and supported the sides. Then I measured how much pull it had. However, I couldn't get past 3/5 throttle as the waves in the tub were swamping the boat and causing the jet to cavitate. So far, my highest reading was 1225 grams, which was pretty impressive considering the boat only weighs 560g. I am sure there is more thrust, I just need a better testing station to get the readings. Now with that out of the way, I am going to mount all of the electronics and cooling lines in the boat and make a new deck. I made the Jv soccer team for my school so now progress will be slow. I will post pics/video whenever I can get out.
Posted on: 8/22/2009 3:45 PM by Author "ISIRC10" in the forum "Speed - Electric"
http://www.rcuniverse.com/forum/fb.asp?m=9036005

RE: The Unofficial all things Jet drive thread
[quote]ORIGINAL: sundogz ISIRC10: Got the boat hull yesterday and you did a great job on the delta. It may be some time before I can work on it, but it will to be a fine boat to be sure. Many thanks Ivan. Sdg [/quote] Thanks, hope you can make the ends meet with that boat. I am sure you will get to it quicker than I would have! Before you do any fiberglass work, I would recommend trying to fit
Posted on: 8/19/2009 7:57 PM by Author "ISIRC10" in the forum "Speed - Electric"
http://www.rcuniverse.com/forum/fb.asp?m=9029256

RE: The Unofficial all things Jet drive thread
Well, looking forward to updates TwinJetMax! As for my other jet boat, it didn't fare too well on the return flight from florida... I had packed it in the dead center of the suitcase, surrounded by soft clothes and blankets. When I arrived and unpacked the bag, It ended up at the top... and the bag had a TSA aproved sticker on it that none of the other bags did. I guess it looked like an IED or something in the xray, but at least they could have placed it back where I had packed it! Well, thanks to their brilliance, I am doing a complete redo of the top of the hull. It was cracked in three places and a substantial peice was missing... boy was I MAD when I saw that! On another note, I have uploaded a video from one of my runs in florida, it isn't particularly incredible (the video). I had taken off the trim tab and the performance didn't change at all, so I figure that I don't need one. In the video, you can see that in turns, it sildes a bit and then the nose digs in and spins out. I am going to try putting a strake down the center of the delta to remedy this problem. Lastly, I finaly weighed the boat with everything in running order and the scale showed 560g (not too bad for a boat this size I think) www.youtube.com/watch
Posted on: 8/15/2009 8:59 PM by Author "ISIRC10" in the forum "Speed - Electric"
http://www.rcuniverse.com/forum/fb.asp?m=9019117

RE: The Unofficial all things Jet drive thread
Well, I'm back from vacation and have finished up the little hull.I fixed the delta and now it looks just about right. Sundogz can take care of the rest when he gets it ;)
Posted on: 8/14/2009 3:39 PM by Author "ISIRC10" in the forum "Speed - Electric"
http://www.rcuniverse.com/forum/fb.asp?m=9016503

RE: Ducted fan build
mb1387, how did that happen? As far as I know, cooling the heatsink should have no effect on the electrical properties of the ESC. srw - That cooling method should work very well, it is essentially what the watercooled escs have, except its all in one peice. I figured you would not be too keen on my idea ;) I havent got the guts to do it with my airboat myself! (and beleive me, its paint job is 100 times less fancy than yours!)
Posted on: 8/14/2009 3:13 PM by Author "ISIRC10" in the forum "RC Airboats"
http://www.rcuniverse.com/forum/fb.asp?m=9016432

RE: Ducted fan build
I am not sure whether I agree with rchamburger... full throttle generates less heat than partial throttle in my experience - I think this has something to do with the ESC offering less resistance to the current coming from the battery? I don't know, I will have to do some research on this before I post any further explanation... About the ESC heating up in the closed compartment - It shouldn't be too bad, my mamba max running a 5700kV on 2s turning an 8.5 by 6 prop gets a bit heated (150-170 degrees fahrenheight) but it doesn't thermal. This is in my airboat and the space in there is pretty confined. You could do water cooling, but then you would be limiting yourself to running on water. I figure that if it doesn't hit 200 degrees after a full run, then you should be fine the way it is, without any watercooling. EDIT: I just noticed that you were going to mount your ESC on the bottom of the radio box. Why not mount it on the bottom of the hull and cut out a little area and replace it with an aluminum plate. That way, with a bit of heat conductive paste, you can watercool your esc without worrying about your pickup snagging weeds or anything.
Posted on: 8/13/2009 1:45 PM by Author "ISIRC10" in the forum "RC Airboats"
http://www.rcuniverse.com/forum/fb.asp?m=9013519

RE: V hull flatty
WOW, that is quite a boat! seems to be leaning in the corners and turning well! And good job with the video as well - I always have my younger siblings do my videos while I drive... I am not very good at driving in a specified area, so having no one filming for me doesn't always turn out.
Posted on: 8/9/2009 6:50 PM by Author "ISIRC10" in the forum "RC Airboats"
http://www.rcuniverse.com/forum/fb.asp?m=9002846

RE: The Unofficial all things Jet drive thread
For me, when I turn, the first half of the range is a slide, not very effective for turning, and then when I exceed that point the boat immediately swaps ends the way only a jet boat could ;) I am planning to fix this by adding small fins to the ride plate I have out back. This is directly under the nozzle of the jet drive, so I am not sure whether its effects will be desireable or not - It could turn very sharply, or it could have no effect on turning whatsoever. Either way, the fins will be in the water all the time so it should make things consistent. An interesting point... after the first run, I must say that the motor and ESC were below the temperature of the water... It seemed as if the water was actually heating the motor up! Then again, I only ran it for about three - four minutes, but that was mostly WOT so I am thinking that my setup could use a higher pitch impeller... Another curious thing that I saw was that my speed was the same when I was at 4/5 throttle and WOT, although I could hear an increase of RPMs... I guess I am maxing out the capacity of the drive? (running 2400kV long 380 feigao on 2100mAh 11.1v Lipo) As soon as I seal the stinkin drive with normal epoxy, I will definitely make a video... This thing is way too fun to drive!
Posted on: 8/8/2009 12:57 PM by Author "ISIRC10" in the forum "Speed - Electric"
http://www.rcuniverse.com/forum/fb.asp?m=8999861

RE: The Unofficial all things Jet drive thread
I had some time to run the boat today and I must say that I was quite impressed. Speed was good, a bit slower than I expected, but an inch of water in the back of the hull was the reason it was riding a bit low. The water was coming in from where the jet drive met the transom. I had sealed it with JB weld because I had nothing better to use, and that just peeled right off. I have to get some epoxy to do the job right. Besides that, I noticed that my turns were slightly innefective in the first half of the range, and then it got super-responsive. I figure that this is because my only strakes are on the extreme outside of the hull, and the only times they are in the water and that only happens then I am in a hard turn. I will try to add strakes to the delta slightly aft of the jet intake. This should make turning more predictable and consistent. The water cooling leak was fixed with electrical tape, rated to have a melting/failing point at 250 degrees fahrenhieht. This fixed the leak perfectly and holds a surprising amount of pressure. I changed the pick up location from the steering nozzle to the stator area and now the flow of water is more like a jet than a stream.
Posted on: 8/8/2009 12:03 AM by Author "ISIRC10" in the forum "Speed - Electric"
http://www.rcuniverse.com/forum/fb.asp?m=8999008

RE: Project - hovercraft?
Ah, yes that is very true about scratch building... Just today, I tried to explain why I was messing around with my boat for hours without end and not getting bored to my cousins. That was quite a pointless conversation as they just didn't get the fact that I enjoyed building things. Btw, I am on vacation in New Smyrna Florida - somewhere in your neck of the woods I presume? That is the reason I have not made any headway on the hovercraft project, I have been messing around with my jet boat while on vacation. Nothing like relaxing on the beach and trying to epoxy a Jet drive in place without getting any sand in there.
Posted on: 8/7/2009 11:03 PM by Author "ISIRC10" in the forum "RC Airboats"
http://www.rcuniverse.com/forum/fb.asp?m=8998873

RE: The Unofficial all things Jet drive thread
Grael, I would like to see if she performs as well! I might be tempted to make a hull simil to that one just for the looks. Now, I have a few questions about the setup of my boat. My water cooling jacket leaks a bit - how do you guys fix this? Where should my cog be on this boat? Lastly, do you think it will need a trim tab out back? I have not run it yet (outside the tub) and am not sure whether I should start out without one or have one from the getgo. thanks
Posted on: 8/5/2009 5:36 PM by Author "ISIRC10" in the forum "Speed - Electric"
http://www.rcuniverse.com/forum/fb.asp?m=8992951

RE: The Unofficial all things Jet drive thread
"I can't seem to locate a hull design I am happy with in the smaller scale (except that first one ISIRC10 showed us! hint,hint)" well, you know what? that hull is of little use to me and it is just laying around on the shelf. I would be glad to see it running. If you feel that you can overcome some of the mistakes I made on it (the delta/deadrise) I am willing to ship
Posted on: 8/5/2009 3:03 PM by Author "ISIRC10" in the forum "Speed - Electric"
http://www.rcuniverse.com/forum/fb.asp?m=8992528

RE: The Unofficial all things Jet drive thread
grael, sorry to hear that. I was looking forward to seeing how yours turned out! My hull weighs 30 grams without the top or any reinforcement. I predict its final weight to be somewhere in the 55-65 gram range when I am finished with the fiberglass and top. I hope 65 grams isn't too heavy. What do you think? Projected date of jet drive arrival: Wednesday, the 29th... won't have much time to test the boat before I leave, but hopefully I should have a working boat by then!
Posted on: 7/24/2009 9:10 PM by Author "ISIRC10" in the forum "Speed - Electric"
http://www.rcuniverse.com/forum/fb.asp?m=8961488

RE: The Unofficial all things Jet drive thread
Well then, happy birthday! does this mean that the little hull is on the back burner for now? I cancelled my order from hobby lobby, placed one at funrcboats, they have the drive in stock. Hopefully mine gets here before the 31st (I am leaving for vacation) My boat is getting there, I sheeted the plug with plywood and then broke up the plug once the CA had a chance to set. still need to weigh it, but right now it is very light. I may want to keep this boat all natural with the finish... I like the look. May post some picts if time allows.
Posted on: 7/24/2009 5:43 PM by Author "ISIRC10" in the forum "Speed - Electric"
http://www.rcuniverse.com/forum/fb.asp?m=8961040

RE: Project - hovercraft?
LOL, I think that I am going to have to make you wait! you see, I could not resist the temptation... I put my brushless motor in it and am doing some final setup work... I need a few more screws to hold the duct down with this kind of power!
Posted on: 7/23/2009 4:42 PM by Author "ISIRC10" in the forum "RC Airboats"
http://www.rcuniverse.com/forum/fb.asp?m=8958316

RE: Project - hovercraft?
LOL, the spokes were found last year when someone trashed their bike trying to jump it... broke the frame in half, and ended up in the hospital... kid was very stupid, hopefully he learned his lesson. Anyway, I picked the bike out of the trash with his permision and stripped it of usefull parts. about the weather... It is pouring again... I am slightly irritated and very wet!
Posted on: 7/23/2009 3:46 PM by Author "ISIRC10" in the forum "RC Airboats"
http://www.rcuniverse.com/forum/fb.asp?m=8958150

RE: The Unofficial all things Jet drive thread
[quote]ORIGINAL: grael Regarding skinning it with ply: I wouldn't. Tougher, and lighter, to spray it with 3M adhesive (or similiar), and tack fibreglass cloth over it in a couple of layers. Then impregnate with epoxy or polyurethane resin and use a stippling brush or roller to ensure the air is driven out fully. Ply will make it too heavy. [/quote] The ply I want to skin it with is 1/32"... It is light, however, I don't know what weight you are acheiving with fiberglass to compare it against. The only fiberglass cloth I have on hand is the heavy bondo stuff, and the foam I am using doesn't like the resin that came with it... Those are my reasons for using plywood. The previous hull that I posted on here (about an inch shorter and 2 inches skinnier) weighed 40 grams, and it was heavily reinforced with fiberglass (I actually stood on it and nothing happened) to tell you the truth, I really don't want to mess with fiberglass, so I will try my hand at skinning it - Is weight really such a huge issue? I mean the power that some of these things have is rediculous for their size. I know that I may regret not heeding your advice later, but right now, I just dont see myself making a fiberglass hull. Thanks for the warning though.
Posted on: 7/22/2009 6:03 PM by Author "ISIRC10" in the forum "Speed - Electric"
http://www.rcuniverse.com/forum/fb.asp?m=8955519

RE: Ducted fan build
I second that ^ Makes me want to do something with the fans that I see online! An idea i have been tempted to try would be a rigger type hull that would be used for speed runs, as it would best utilize the lower COG of the ducted fans. Just an idea though...
Posted on: 7/22/2009 3:33 PM by Author "ISIRC10" in the forum "RC Airboats"
http://www.rcuniverse.com/forum/fb.asp?m=8955122

RE: The Unofficial all things Jet drive thread
Well guys, all of your building has got me jealous so I figured I would start another purpose built hull for the jet drive. My hovercraft project is drawing to a close and I want to have something to do. The new hull is going to be 13" long and 6" wide - considerably wider than my previous one. The delta is 1.5 inches wide and I have a 1 3/4" high transom. It has a 23 degree angle of deadrise, which is constant throughout the entire length of the hull. What do the experts think? Does it pass that test? If she does, then I will waste no time in skinning her with thin ply. If not, then I will make corrections or a new plug as the foam is very cheap. This hull, as with most hulls that I make, has been designed by me, mostly through hand shaping and cutting the angles on my table saw for accuracy. I checked the feigao 380L that I ordered and that thing is a beast so I think that the larger size of the boat should make it more stable. What do you guys think - Should I move forward with it?
Posted on: 7/21/2009 9:03 PM by Author "ISIRC10" in the forum "Speed - Electric"
http://www.rcuniverse.com/forum/fb.asp?m=8953145

RE: Project - hovercraft?
Well, this is the second time I am posting this... stinkin proxy server timed out! Attached are the pictures that I promised. The rudders are made out of 1/8" plastic (cut from a sign that my Dad brought from his work) and they are connected buy a pushrod out of the same material. These rudders are attached to the craft by hinges made out of 1/4" square pine blocks that are epoxied to the three supports that I installed previously. I used old aluminum bicycle spokes as they allready have threads on one end to hold everything together. I carefully drilled holes into the rudders and screwed the spokes in until theey were in all the way. Then I trimmed and bent them into an elbow so I would be eable to remove then if I ever needed to with ease. The rudder to servo linkage is also a spoke, however I used the other end, which is bent at a 90 degree angle that stops it from falling out of the arm. I make the arm out of aluminum angle, whith varying mounting holes if I ever needed more or less deflection. After that, it was time for testing. It had been pouring outside all day so I was limited to indoor running. The speed was more than I needed in an enclosed space, so I think I may need to add a rubber bumper too keep the walls in my room intact. Every turn was a power slide until I pegged the throtle and countersteered, but soon I got the hang of it. This thing is so fun to drive once you get used to it. Now I need to stop messing around with it and get back to work. Ken still needs a way to control his hovercraft, and the OCD in me is pestering me about the section of deck that has still not been painted. Once it stops raining, I will go outside and take some video. So far, the top speed is about 10mph, but I am happy with it. This thing rocks! you guys don't know how satisfied/relieved I am that it works as I expected it to. BTW, I have a name for her... Electric Slide! (its an electric and every turn is a slide )
Posted on: 7/21/2009 8:48 PM by Author "ISIRC10" in the forum "RC Airboats"
http://www.rcuniverse.com/forum/fb.asp?m=8953103

RE: Project - hovercraft?
Thank you all for your kind suggestions and offers. srw1960 - I think that you better save those hinges for your upcoming hovercraft project... you are gonna need them! I was not able to post my progress today because I had a lot of stuff on my hands... and I pulled my hamstring muscle a bit during the weekend. However, I was able to make the rudders on Sunday, and boy did they turn out great! (IMHO) They are very smooth and easy to turn yet they don't woble at all. They have 160 degrees of rotation before any binding occurs and I don't think that I even need that much. They are all removeable and can be fixed easily, and weigh slightly less than an ounce all together. I will add pictures and a description of the build process in the next post - my camera battery needs to charge.There is a minor down side to the new rudder instalation - I have to change my lift fan switch location, but I foresaw that problem and only tacked the switch on with a bit of CA when I installed it. I guess I will have to make a clever linkage for this one. about the lobster boat - my friends call it the lobster boat because with its "unique" cover and sponsons, she resembles a lobster... and she used to be a slow one at that. That was before I put a BL and Lipo in it. On Saturday I brought her to the river with me and drove around. I still need to sort out my COG and turn fin, as she is slightly unbalanced, but even with that, she Gps'd at 32 mph in a calm pool. If you like, you can see the thread in the electrics section (predator outrigger build)
Posted on: 7/20/2009 9:53 PM by Author "ISIRC10" in the forum "RC Airboats"
http://www.rcuniverse.com/forum/fb.asp?m=8950372