JAE Heat racing

[HOTWATER]

I was out testing my 21 jae and it kept blowing off and or hopping in the turns it is fast but for heat racing in chop or a little wind or even crossing your own wake on lap 2 .....I am not impressed i have the boat setup per instuctione etc...and I will prolly get beat up on here but i am not that impressed....YET

Mine is built right and true and square...

Fire when ready

no need to fire! the boat should not blow off.. i seen where jim mamarill had his blow off too, i have run well over 80 and NEVER blown off the water,i have also NEVER had any hop in the turns with the jae style boats..what turnfin are you using? i tried the turn fin from zippkits and it was very very lifty for me, rf sponson wouldnt stay on the water,if thats what u have you may have to work on it...what props are you guys running and what is your strut angle? also, put your boat on a table sitting on sponsons and ski, the bottom of the tub should be level to the table, if its low in the back that is no good...something is definently not right, there are lots of these boats running great out there so it is there you just need to find it...MT

I opened up the original drawings of the JAE .21G2 and it looks to me that the boat built as stock will have an slight positive AoA of the tubs bottom - depending on what plywood sheeting one uses of course on the sponsons and ski... See attached picture.

If you add the overhang suggested in the build plans it will raise it even further, I checked mine last night and there is about 1/16 difference.

Hey Jim! ...Have you tried added any neg to your struts? Just curious since it has been brought up here...

-Kent

Kent, I have not tried it yet. I have been pretty happy with the setup so far. I will machine about 1 degree neg on the back of my mount and give it a try then report my findings. I think I will also try nothching the bottom of my strut where it sits on the ski and get it down a little farther. I have not experienced the symptoms that Terry has mentioned with hopping but it makes me curious as to the cause.

Jim

Thanks Jim! Let us know if anything changes...my belt sander can give my strut an update if needed!

-Kent

 

[tmunn]

Guys , i was not trying to start a poo poo match I was just giving my observations and looking for some advise.No dig at the designers i think their great...I am mostly frustrated because myself who i would say is a very cautious measure everything 5 times guy ...cannot get this boat to run off the bench like seemingly others can....Sorry if i offended anyone..

After measuring and measururing and head scratcing for hours this evening and reading what everyone was saying In particular the comment Ron said about measuring everything ....i decided to take some pictures and measure and noticed that the non fin side sponson Tip was much higher in the nose 1/8 " or so .I looked and looked and looked some more.....I could see one CF tube was sprung a bit and had some pressure on it when inserting it in the brass that was glued to the sponson......so after humming and hawing and much contemplation i checked the to see the tubes were parallel to the building board and i did not have them epoxied in the tub crooket(spelling).They looked good and exact spacing between them from front to back on both sides and they ran parallel with the setup board.

I put the sponsons on some short 4" long Cf peices as guides and slid the sponsons together (facing each other like they would be on the boat )till the brass tubes touched and the sponsons were identical to each other ....more head scrathing....I removed the short CF rods and grabbed some long spares and I put both CF rods in one sonson at a time and layed the tubes on my board with the sponson upside down and hanging over my board and the the TF side was dead flat but .....when i put the CF tubes in the left sponson and put those tubes on the building the rear tube was up in the air and off the board aprox.3/8 at 16" from the inside of the sonson edge....

So then i put the sponson together using my spare rods and did some checking on the table again ..What i found was.....The left sponson tip was aprox.3/16" higher in the air than the turn fin side...i said that cannot be good...

This is getting to long so I will sum it up.I heated and removed the rear brass tube.Releived some material and re-installed a new brass tube with no pressure or stress on it.There is no load on them now or not sprung in anyway.

If the AOA and the sponsons are suppose to be the same on both sides then I should be good as far as the boat being true and straight now if the left AOA is different from the right like on my Other rigger then I am Screwed for now...

The brass tube must have moved when i glued it originally or the holes in the ply were misaligned ...who knows

NOW when the sponson are together on my board and resting on the back of the first overhang on the sponson as well as the second (which is also the ride pad) they are dead flat and no rocker . no pressure on the Brass that hold the CF rods in the sponson.They are being epoxied overnight tonight and i am heading to bed....

Please someone tell me that the sponson AOA are both the same and what i did was a good thing.

Once this is rectified i will work on some neg strut angle and go from there.

Ron I took pics and uploaded them but they are not good quality.I will take some more but i wanted to say my strut is down on the ski and has no negative in it.

sorry for the type o's it has been a long day...

Terry

 

[Ron Zaker Jr]

I was out testing my 21 jae and it kept blowing off and or hopping in the turns it is fast but for heat racing in chop or a little wind or even crossing your own wake on lap 2 .....I am not impressed i have the boat setup per instuctione etc...and I will prolly get beat up on here but i am not that impressed....YET

Mine is built right and true and square...

Fire when ready

no need to fire! the boat should not blow off.. i seen where jim mamarill had his blow off too, i have run well over 80 and NEVER blown off the water,i have also NEVER had any hop in the turns with the jae style boats..what turnfin are you using? i tried the turn fin from zippkits and it was very very lifty for me, rf sponson wouldnt stay on the water,if thats what u have you may have to work on it...what props are you guys running and what is your strut angle? also, put your boat on a table sitting on sponsons and ski, the bottom of the tub should be level to the table, if its low in the back that is no good...something is definently not right, there are lots of these boats running great out there so it is there you just need to find it...MT

Martin,

If you build the kit exactly as it comes and use the existing boom tube holes with the ski attached, you will have a tub that is low in the rear. Approx 7/8" in the rear and 1" at the front. To get the effect your talking about where the tub is level front to back, you would have to raise the rear boom almost 1/8". This being the case, should the ski be taller or should the rear boom be raised? Raising the rear boom would drastically change the sponson attack angle. How did you get the attitude of your hull flat from front to back? And what is your angle of attack on your front sponsons?

Ron

I checked my kit boat last night on a flat table. The rear of my boat is .058 lower in the rear. No real issue either way.

 

[Mike Larson]

I did, file angle on my strut, at the transom, nominally, and have a notch where it sits on the ski... nominally..... with the idea, almost per understanding Rod's strut drawing, and keeping the angle of my strut with the angle of the ski ( mamaril).

Basically, i didnt count for epoxy, and paint during rough in, and final post paint assembly had a positive angle that made me sick

End result, with keeping with this angle, per straight edge, and basically shim stock checking clearance along the length of the strut.

Instant launch, no ill effects, and not even a hint of blowing off...... the boat's new, and I havent even set to whooping on it yet. I do have mind of more negative, if, it shows flight...... approaching heat speeds.....

Rod, has the very free thing right on, for to me, it planes like a water spider....... a very fast water spider.....

Personally, I have realized that, the thought behind this hull, is seriously there.... One simple boom measurement adjustment took the limited and only quirk I had right off the stand...... while, I wont be an 80's guy, nor search for it, mid 60's off the stand on the 4th tank, and I'll take it up from there........ easily, because i think, again, the team made it foolproof..... on purpose.

Thanks to the JAE team, again, because, I am the monkey, that could, and did, build it..... in reality, with a dremel, and a sanding block....... kit, and per instructions.

I havent checked angles.... but could shoot my numbers out, if youd like.... i didnt see the need, to check, after seeing the first tests..... Keep testing, and hang on. Mike

 

[TCHedOff]

Terry, I believe you've just explained the cause of your problem(s)! You said,

"NOW when the sponson are together on my board and resting on the back of the first overhang on the sponson as well as the second" :huh:

(Rod/Ron/Martin.... confirm this for me.... maybe mine bottom was wrong last summer?!? but it worked well enough).

When your boat is sitting on a set up table, ONLY the rearmost sponson ovehangs should be contacvting the table - "first overhang" should be up off the table.... when these boats run at speed they should only have the rear-most part of the sponson surfaces contacting the water (and then only every-so-often - not constantly).

Having the 1st overhang touching the water is basically giving you a HUGE AOA to the water (water is never perfectly flat) - and when the water hits that hi AOA surface its gonna force the front of that boat up harder, higher and faster than (c'mon Rod - you're the 1 line master :lol: ).

Anyhow, I'm pretty sure that is the source of all your problems.... it explains the blow offs, the tendency to get unruly crossing wakes, and perhaps the hopping. Hope so!

 

[Ron Zaker Jr]

Terry, I believe you've just explained the cause of your problem(s)! You said,

"NOW when the sponson are together on my board and resting on the back of the first overhang on the sponson as well as the second" :huh:

(Rod/Ron/Martin.... confirm this for me.... maybe mine bottom was wrong last summer?!? but it worked well enough).

When your boat is sitting on a set up table, ONLY the rearmost sponson ovehangs should be contacvting the table - "first overhang" should be up off the table.... when these boats run at speed they should only have the rear-most part of the sponson surfaces contacting the water (and then only every-so-often - not constantly).

Having the 1st overhang touching the water is basically giving you a HUGE AOA to the water (water is never perfectly flat) - and when the water hits that hi AOA surface its gonna force the front of that boat up harder, higher and faster than (c'mon Rod - you're the 1 line master :lol: ).

Anyhow, I'm pretty sure that is the source of all your problems.... it explains the blow offs, the tendency to get unruly crossing wakes, and perhaps the hopping. Hope so!

correct it's a 3 point footprint.

 

[Ron Zaker Jr]

Guys , i was not trying to start a poo poo match I was just giving my observations and looking for some advise.No dig at the designers i think their great...I am mostly frustrated because myself who i would say is a very cautious measure everything 5 times guy ...cannot get this boat to run off the bench like seemingly others can....Sorry if i offended anyone..

After measuring and measururing and head scratcing for hours this evening and reading what everyone was saying In particular the comment Ron said about measuring everything ....i decided to take some pictures and measure and noticed that the non fin side sponson Tip was much higher in the nose 1/8 " or so .I looked and looked and looked some more.....I could see one CF tube was sprung a bit and had some pressure on it when inserting it in the brass that was glued to the sponson......so after humming and hawing and much contemplation i checked the to see the tubes were parallel to the building board and i did not have them epoxied in the tub crooket(spelling).They looked good and exact spacing between them from front to back on both sides and they ran parallel with the setup board.

I put the sponsons on some short 4" long Cf peices as guides and slid the sponsons together (facing each other like they would be on the boat )till the brass tubes touched and the sponsons were identical to each other ....more head scrathing....I removed the short CF rods and grabbed some long spares and I put both CF rods in one sonson at a time and layed the tubes on my board with the sponson upside down and hanging over my board and the the TF side was dead flat but .....when i put the CF tubes in the left sponson and put those tubes on the building the rear tube was up in the air and off the board aprox.3/8 at 16" from the inside of the sonson edge....

So then i put the sponson together using my spare rods and did some checking on the table again ..What i found was.....The left sponson tip was aprox.3/16" higher in the air than the turn fin side...i said that cannot be good...

This is getting to long so I will sum it up.I heated and removed the rear brass tube.Releived some material and re-installed a new brass tube with no pressure or stress on it.There is no load on them now or not sprung in anyway.

If the AOA and the sponsons are suppose to be the same on both sides then I should be good as far as the boat being true and straight now if the left AOA is different from the right like on my Other rigger then I am Screwed for now...

The brass tube must have moved when i glued it originally or the holes in the ply were misaligned ...who knows

NOW when the sponson are together on my board and resting on the back of the first overhang on the sponson as well as the second (which is also the ride pad) they are dead flat and no rocker . no pressure on the Brass that hold the CF rods in the sponson.They are being epoxied overnight tonight and i am heading to bed....

Please someone tell me that the sponson AOA are both the same and what i did was a good thing.

Once this is rectified i will work on some neg strut angle and go from there.

Ron I took pics and uploaded them but they are not good quality.I will take some more but i wanted to say my strut is down on the ski and has no negative in it.

sorry for the type o's it has been a long day...

Terry

are you saying that you have 2 overhangs touching the table on each sponson while the boat is assembled,or sponsons off the boat???

 

[TCHedOff]

Terry, IF I understood you correctly, you've managed to build a 5 point hydro!

 

[tmunn]

NO<<<NO<<<NO<<<<<

The illustration that I gave was with the sponsons off and attached rogether with very short CF rods then i just placed them on the board by hand resting on the two overhangs so i could really eyeball them.In order to acheive what i was dooing the rear of the sponsons would need to be way up in the air .....and the nose down.

I was just trying to illustrate that with the sponsons off the boat and the rods installed that the sponsons NOW rest nice and level on the board no rocker ing no one tip higher than the other etc...

It was late and i was tired.Sorry for any confusion.....

I say the brass tube on this one moved or got missalinged during the epoxy stage...

Now after all that ......Are the left and tight sponsons suppose to look identical and have the SAME AOA ??

Mine do and if so then on to the Strut and checking My CG.

What is the range that seems to be working for CG with tank empty.

I appreciate all the help and comments .I thing the sponson issue was a huge one..

 

[TCHedOff]

DANG!!!! I thought I had it figured out! (and wish I had!)

"Now after all that ......Are the left and tight sponsons suppose to look identical and have the SAME AOA ??"

YES

CG - Rod said the sweet spot is about 6" long and dont matter... but time for me to shut up.

 

[jason lowe]

Jim, When you suggested making the sponsons wider, what width would you go with? I am currently building a .21 and would like some advise! Thanks- Jason

OK guys I have gotten thru our first district race with both my .12 and .21 JAE's and I have a few observations to share. First a little background. I started RC boating in the early 90's and raced mainly tunnels but did dabble with a couple riggers and hydros. I then took 12 years or so off from racing and got back into it last year. The JAE's are the first Riggers that I have ever raced that I built myself which is very satisfying.I have only run my boats in testing so this first race was a real eye opener for me. So with that said here is what I learned this past weekend.

1) These boats are a hoot to run.

2) If you run hard into the turns they actually accelerate thru the corners, it seems like a sling shot effect.

3) If you have to cross another boats wake it is best to get off the throttle a bit first.What I noticed is when I had to cross over and kept it at full throttle it would raise the front of the boat up and when it came down it would bounce forcing the nose up even higher causing it to blow off. A good lifting prop may help but I am not an expert. Also getting the prop as low as possible as the JAE team suggests is a must.

4) They are both very stable in race water except for the previous observation. A wider foot print of the sponsons may make them even more stable, I will have to test it to find out.

I did end up winning both classes but I have to admit that with the .12 I did not run against any other .12 riggers, it is a .18 hydro class which any thing upto .18 can run. In the .21 class it was a race of attrition and I ended being the luckiest one out there. My boat did run very well and I think I held my own reasonably well against an experienced racer in our district who has won a few national titles and has a very fast boat. Overall It was a very positive experience and outcome for the start of the season. We'll see how the rest of the season pans out.

Thank's for reading, Jim

 

[Jim Mamaril]

Jim, When you suggested making the sponsons wider, what width would you go with? I am currently building a .21 and would like some advise! Thanks- Jason

OK guys I have gotten thru our first district race with both my .12 and .21 JAE's and I have a few observations to share. First a little background. I started RC boating in the early 90's and raced mainly tunnels but did dabble with a couple riggers and hydros. I then took 12 years or so off from racing and got back into it last year. The JAE's are the first Riggers that I have ever raced that I built myself which is very satisfying.I have only run my boats in testing so this first race was a real eye opener for me. So with that said here is what I learned this past weekend.

1) These boats are a hoot to run.

2) If you run hard into the turns they actually accelerate thru the corners, it seems like a sling shot effect.

3) If you have to cross another boats wake it is best to get off the throttle a bit first.What I noticed is when I had to cross over and kept it at full throttle it would raise the front of the boat up and when it came down it would bounce forcing the nose up even higher causing it to blow off. A good lifting prop may help but I am not an expert. Also getting the prop as low as possible as the JAE team suggests is a must.

4) They are both very stable in race water except for the previous observation. A wider foot print of the sponsons may make them even more stable, I will have to test it to find out.

I did end up winning both classes but I have to admit that with the .12 I did not run against any other .12 riggers, it is a .18 hydro class which any thing upto .18 can run. In the .21 class it was a race of attrition and I ended being the luckiest one out there. My boat did run very well and I think I held my own reasonably well against an experienced racer in our district who has won a few national titles and has a very fast boat. Overall It was a very positive experience and outcome for the start of the season. We'll see how the rest of the season pans out.

Thank's for reading, Jim

Jason, The distance from the tub to the inside of the sponsons on a stock kit is approx. 7 1/8" , I beleive some one on here suggested 8 3/8 , I will try other options before I widen the sponsons.One step at a time. Some one asked in an earlier post what prop I was running, I am running a b/c and pitched 1452 from Mark Sholund, It is an awesome prop but I have others to test.

Jim

 

[tmunn]

I have a pic of what i was trying to explain but the long story short is now i have the identical measurment from table to tips for example ......from table to the first step for example .....and the sponsons are a mirror of each other when you put them together like in the pics on short peices of CF tubing.

What would you guys think a 9-1/8" spacing from the outside of the tub to the inside of the sponson would act like.

I have some 24" Rods i was thinking on tring and that is what the spacing works out to be.The supplied rods are 20" in my kit..

All comments welcome Todd keep em comming guys..

When the boat is assembled and i take some measurement the sponsons seem fine now .

The distance from the table to the rear of the tub at the transom is .031 lower than the distance from the tub to table taken in the tank area.

My strut bottom runs parellel with the building board when the boat rest on the sponsons and the rear of the ski.

I am thinking cut a notch in the ski, lower the strut and put some neg on it but don't want to go overboard and past what is needed.

What would the suggested washer thickness be if i wanted to put one between the transom and top of the mout to get me the 1 degree negative if that is what i should be shooting for ?

Sorry guys.... aint the best at splaininthings

 

[moparbarn]

grim has said that .012" is worth 1/2 degree, in the villain kit instructions. i know that he is referring to an ob, but it shouldn't make any matter. angles are angles, strut or lower unit..............so, .024" should be 1 degree.

 

[dave roach]

.017 per inch is 1 deg.

Dave Roach

 

[tmunn]

Guys after my repairs to my misalighned sponsons and adding some negative and cutting a peice out of the ski and lowering the strut..... The 21 was running much better till the fin bent.

It did not seem to want to blow off like it did last time out .i had too much neg in and i couls see it pushing the sponsons down. So i removed the washer and put some shims in there made from a soda can aluminum

Prior to that on a really nice pond...When I come back around a whole lap on dead calm water and hit my own wake and cross it the JAE seemed like and for lack of a better word come unhooked and hop or jump sideways then something would dig in and I would be upside down.

It is nor so mad if you can stay in clean water but crossing a wake it takes flight....

Is the a better deeper stonger turn fin that I can get...quickly....

 

[John Knight]

Terry,

I bent the Zipp kit turn fin which is not 7075 aluminum material. I bent an identical 7075 turn fin that was shaped to the kit fin. It bends on the trailing edge just below the sponson. I ordered a new fin from David Preusse (847) 526-4694. It is not exactly like the Zipp kit in shape. I ran it yesterday for a short bit and it did not bend. It is 7075 material. I believe it is better in shape and design and more closely looks like a Sport 40 turn fin. I know that Kentley and Martin T. are using the Preusse fin. Add me to the list. I strongly suspect the kit one will continue to bend with other boats. It is an exceptionally long fin with little sponson to bolt it to. The pressure dynamics on the fin in the turn causes it.

BTW, when you cross a set of wakes, you need to slow down some to give the rigger a chance to settle down and get through the waves. Even with a 90 rigger you need to back down the throttle or you will turn your boat into a tumbleweed or stuff it.

 

[tmunn]

I sent an e-mail to Dave and am awaiting a reply...i use his cowls..I am use to going WOT through much rougher stuff than a wake with my midified hawk.Perhaps it is slower and if for sure has different sponsons .

Thanks for the tips..Are you going to the carolina showdown john ?

 

[John Knight]

I sent an e-mail to Dave and am awaiting a reply...i use his cowls..I am use to going WOT through much rougher stuff than a wake with my midified hawk.Perhaps it is slower and if for sure has different sponsons .

Thanks for the tips..Are you going to the carolina showdown john ?

Just remember the JAE is a much different animal that all of the other riggers on the market. It will ride and react differently from the others. Just the nature of the design and there is a learning curve for the owners. Just like the Eagle does not act like as a Roadrunner, Hawk, Hummingbird, etc. The design and running characteristics are different.

If I can go to the race, I will. The health condition of my wife will dictate that and I should know by the end of this weekends World Tunnel Championships. Good chance I will be going.

 

[raytam]

I hope I'm not hijacking this thread, but here's a video I took of one of the racers at my pond. It's suppose to be a heat race of two JAE 12g riggers, but one had engine problems. This is one crazy boat. THanks

Ron

http://www.youtube.com/watch?v=ckXzezgxBDo