Wednesday, May 27, 2009

Kep's .21 '09 pics

DIY pipe mount made out of a K&S brass strip, a plier, Staybrite flux, silver solder and a hot Ungar iron... :) I think it works good. It's the same design that I included in the Freebie drawings. The base plate is a 1 mm thick GRP plate with 5 mm holes for the rubber grommets. The grommets have 3.5 mm long K&S brass tube spacers in them.

The two holes U see to the right is charging connectors glued in place with epoxy. No need to remove the self adhesive plastic covers for charging. :)

The mounting screws through the tub deck are stainless 4-40 screws with low-profiled aluminium nylock nuts. Under the tub's 0.8 mm thin plywood deck is a 5 mm thick plywood as reinforcement.

The nylon screw is a "plug" to reach the Futaba on-off switch which sits below. It's the same 1/4-20 threaded screw we use for the motor mounts "covered" with a large diameter Du-Bro silicon tube so its seals against the hole in the tub deck.

All CMDi running gear I pulled from another boat. The strut "blade" is cut down to make it lighter. It sits on top of the prop-support "ski" ramp. About 0.5 deg negative AoA on the strut (I have not messured it though - yet).

The CMDi rudder blade is made lighter and the base also... Notice the hollow shaft... ;)

I have for three years used aluminium 6-32 screws and nylock nuts as fasteners for the strut mount and rudder. I have never broken one!

Bought @ Fastener Express.

This is an Eagle type of cowl bracket made out of 0.8 mm polycarbonate that I bent at 90 deg. The screws are normal stainless 4-40. There is a low gaboon plywood doubler on the inside of this bulkhead so there is less chance of drilling through inside the nose... The nose is hollow btw.

I make the tank mount "loops" out of 1.4 mm K&S music wire. There is a loop at each end that the 4-40 screws go through. You must heat the wire red-hot with a open flame torch before bending, and then re-heat, and bend, and re-heat... Well you get the picture... :)

I mostly use a thin strip of fiberglass tape as tank hold downs that go around these wires... I'll take some photos later of it when the tank is strapped down if you still dont understand it. LOL

The 10 x 8 mm carbon fiber tubes we use are kind of fragile. So we reinforce them with a sewing thread (the thick one - we call them bear-threads in Sweden) and CA glue. The blue screws & nuts are 1/2" long 4-40 aluminium.

CMB "green head" Valvola .21 motor. Yes, you have an issue with your monitor - its green...! ;) Maybe not... Zoom .21 carb with reversed arm to clear the cowl. Its a tight fit.

Starting belt is Aquacraft GrimRacer 15" and yes, the motor is not in the middle of the tub. :)

Futaba servo horns as cowl locks. The small U-loop between them is a pressure tube holder made out of 1 mm K&S music wire. Aquacraft GrimRacer pushrod rubber seals is used. Kalistratov fuel needle. The rear cowl "seats" are made out of left-overs from the gaboon plywood tub sides. Recycle! :)

Do note, no links are used on the S9650 servos - Z-bends on the Du-Bro .072 wires, it cant be easier or lighter then that.

0.8 mm carbon fiber sheeted transom on booth sides. Aluminium 6-32 screws from the inside of course. The two outer aluminium washers need to be cut down slightly to clear the tub sides.

FAAST receiver is under there... S9551 steering servo. U can see the 1 mm thick GRP plate for the Futaba switch here also.

Mikael Sundgren type of DIY hold-down "hooks" are used for booth the battery pack and receiver. I'll publish an detail shot of it later on.

Female 2 mm dia charging lead adapter is glued in from below. U can see the 5 mm thick plywood deck doubler here also.

K&S brass tube as antenna tube mount.

Tuesday, May 26, 2009

Swedish nats round 1 FSR-H & OTA

This info will be in Swedish from now on... ;)

Nu är det dags att dra igång den Svenska heatracing och katta säsongen! Tävlingen är den 6:e och 7:e Juni i SSAB's kyldamm i Oxelösund.

HÄR hittar ni den officiella informationen. Men ni kan läsa den här nedan också.

Oxelösunds Marinsportklubb inbjuder till SM-1 i heatracing den 6 & 7 juni 2009 på sötvattendammen i Oxelösund.

Tävlingen omfattar FSR-H3.5, FSR-H7.5, FSR-H15 och OTA.

Klasserna H3.5 och H7.5 körs på lördagen. Första start klockan 10.00.

Träning: 9.00-9.45 för klass H3.5. Träning för klass H7.5 under lunch timmen.

På söndagen körs klass H15 och OTA med första start klockan 10.00. Körschemat bestämms efter de rådande väderutsikterna.

Medlemskap i SMBF skall kunna styrkas. Tävlande skall med anmälan uppge sina tilldelade frekvenser eller fyra olika godkända frekvenser om ingen finns tilldelad.

Anmälan skall sändas via e-mail till Fred Brihagen senast 10 dagar för tävlingsdatum (dvs den 27:e Maj!). Anmälan är bindande, vilket innebär att avgift skall betalas oavsett start eller inte. Startavgiften betalas vid registrering.

E-maila anmälan till Den här e-postadressen är skyddad från spam bots (du måste ha Javascript aktiverat för att visa den.)

Startavgift är 150 kr för första båten/klassen och sedan 50 kr per båt/klass. För juniorer är avgiften 75 kr för första båten/klassen och 25 kr per båt/klass.

Övernattning på vandrarhemmet Poppeln kan rekommenderas.

Välkomna till en trevlig racinghelg!

FSR-V SM3 & GP in Eksjö June 13-14

If you have'nt registered for the Swedish FSR-V GP (and Swedish nats round 3) in Eksjö it's time NOW! The last day for register is June 7.

Monday, May 25, 2009

First test of Kep's .21 '09

This is me testing one of my new Kep's .21 "09" riggers yesterday in Oxelösund. The video shows it being in the drink for the second tank of fuel ever. The CMB "green head" Valvola engine is brand new also - I'm running it in in the video... The boat set-up was done at home according to my drawings and it was not handling too shabby in the quite choppy waters... ;)

In the video it runs a stock "right-out-of-the-bag" Aquacraft GrimRacer 44x66L prop. With that I mean: it was not sharped, balanced or cupped = right out of the bag... Its a very good starting prop for running in a new .21 rigger engine I think. The GrimRacer 45x68L is also a good start prop.

First let me make it clear - the "09" version is not at this point meant to be a new "Freebie". It's not even developed yet, I even have different versions of it with different sponsons...

The main things different vs the Freebie is this:
- Wider tub with off-set motor and drive line.
- Slightly different front shape of tub.
- Different sponson tube spacings.
- New front sponsons (in all we have three designs to test).
- Prop-support ski ramp with a "step" - no rear sponsons.

Other notes:
- I have two of them myself, booth are prepared for running Valvola or Sirio engines.
- Total weight "RTR" with no fuel and no prop: 1750 g / 3.86 lb / 61.73 oz.
- Afterplane length measured from back face of drive dog to trailing edge of front sponsons: 575 mm / 22.63" (same as Freebie).
- "Prop" weight is 449 g / 15.84 oz (measured with the rudder blade on the scale).

Later that Sunday when the water was smoother it did about 102 KMH / 64 MPH with the engine still not run-in and the set-up not changed. Now I need to make some new turn fins, blend some new fresh fuel, sand the running surfaces of the ski and sponsons flat and smooth and test some more... :)

Micke is not ready yet with his Kep's .21 '09 rigger so he tested his Kep's "06" instead. This one is very close to the Freebie design. Today it did 103 KMH with a 3.46" H6 prop from Mark Sholund.

Micke's SGX 45 is quite good in choppy waters but a "dog" when its smooth... Here it's a little loose.

A little more airborne... U think its all good? Think again... LOL

Oops. This is going to end in a BIG splash... And it DID.

First tunnel test of '09

Yesterday we where at our new club pond in Oxelösund (Micke and me have changed our club to Oxelösunds MSK for this season). It was mostly good weather but quite choppy conditions. This video shows the second time Micke's stock Aquacraft VS1 tunnel boat was in the water, ever. It has a stock K&B .21 engine running 30% O'Donnell boat fuel and most likely an JG prop. ;)

As you can see in the vid, the buoys aren't in the water yet. In Sweden we also race the stock tunnels in a triangular shaped course and with a standing start from the pontoon. TOP speed is not the most important for good performance here...

This is my VS1 as seen in my earlier blogs... I tested it once - then a steering servo broke... Crap. During my short time in the wet it showed some nice handling and its way easier to drive then the TS2. :)

Saturday, May 16, 2009

Building the VS1 part II

I built my VS1 tunnel ready today... First I checked all the joints in the hull where the different plywood parts join and added some CA glue where it was needed.

Then (as per instructions) I blue-printed the bottom of the sponsons with a flat Great Planes sander. The idea is to match the left sponson with the right so when you put the boat on a flat set-up surface there will be no "tweak". Then also to make the rear riding surfaces completely flat... Do it with 80 grip paper first and finish it with 150. If you sand through the clear coat you need to re-seal the wood. Use an automotive 2K clear or epoxy finishing resin (like ZAP). If you use the finishing resin brush it on and leave if soaking in for a while and then wipe most of it off with a lint-free paper towel. After the clear or resin has hardened over night re-sand it slightly with 150 sanding paper again...

One big advantage with the O.S. motor is that you can adjust/shim the steering pivot pin angle to what you want it to be at separately from the AoA of the prop. If you look at the first picture here above (upside down) you see that I first attached just the motor mount base to the VS1. Its much easier to check the hinge pin angle then vs the flat set-up board when the rest of the motor is not in the way... Shim it so its at least at 90 deg to the "water" to begin with. I'm no tunnel expert so I'll come back with some more set-up guides as I figure it out...

Then I assembled the rest of the lower end of the motor to the rig and set the AoA of it with a digital angle finder on top of the spray plate. The hight of it I set at so the round "bullet" is just above the set-up board.

Its also a little easier to make the steering cable assembly without the engine in place also. I opted for using Sullivan #508 wires. There is nothing wrong with the stock wires but I just like the Sullivan's better...

I use Futaba S3305 for steering and Futaba S3115 for throttle.

The stock VS1 steering pull-pull wheel is used. its made for the stock Futaba 35 mm servo disc. In this picture you can see that I also used the extremely flexible Sullivan #507 cable for the throttle - its only 0.8 mm in diameter and the drawback of that is that the outer nylon tube is tiny also. But I used the stock VS1 nylon tube as a step-up adapter by using a 2 mm drill-bit and opened the hole slightly so it could be pushed over the Sullivan tube... A drop of Zap green CA glue at each end and it's done... :)

You can also see that I opened up the holes for the Sullivan #508 nylon tubes in the plastic guide so I could run them through it... I CA glued them to the plastic guide plate.

Ps. don't forget to add some silicone sealant or Zap-a-dap-a-goo between the plastic guide and the box before you mount it to the box...

The other end of the tiny Sullivan throttle cable also got the same step-up stock VS1 nylon tube "adapter" over the tiny Sullivan 1.8 mm nylon tube as I did at the radio box. But this one is so short you can get away with not opening up the hole at all in the white stock tube. Its a tight fit though. A drop of CA glue between the nylon tubes and they cant slip-n-slide...

I made my own metal tank with a hopper for the VS1. I will test if its any noticeable difference vs the stock tank (that is a really nice unit BTW).

I balanced it at 219 mm with two packs of Great Planes GPMQ4485 self adhesive lead weights. This is where the bulk of it is placed and then the rest is inside the radio box floor.

A front view of the tank.

I made a very simple oiler for the motor. It's made from a simple 2 mm thick fiber glass sheet with two holes where I bolted an 1/8 off-road fuel filter holder to... Simple and clean. :)

One of few things we can modify on out motors (we only run the stock class) is to make the fins sharp. So I did. The other modification we can do to the motor is to re-shim it so I removed the shim completely for added torque.

This is how it looks with decals on it.

We have a fixed national starting number on our tunnels all season - mine is #5 this year...

So now its basically done - it's a few items to fix before testing but not much. This will be fun! :)

Ps. the RTR weight (no fuel) ended up at 2400 g.