About CG

A few posts down I talked about placing the components to get the correct range of CG before fastening everything in place.

Here is a picture with the correct CG as provided to me by HP. Its measure from the step nearest the aft of the boat

Drive installation complete and more

OK, so I have finished pretty much everything for the drives. Shafts are now glued in place as well as the shaft support's, motor side. I also glued in the servo mount for the rudder.



Below you can also see the battery mounts which I cnc'd to make room for some straps and access ports to get underneath them.



Now I have started looking at how I am going to layout everything in the hull to get a correct CG with the possibility to move the CG point forward and aft by about 2cm.
Will look something like this though missing from the shot is the Rx and the Rx battery which will be placed fore of the servo mount which is prefect since this will add some weight behind the CG point and allow me to move the big Lipo's forward.

Summer 09!

Well, summer is here and I have decided its time to try an finish this project!

So the last couple of days I have been busy gluing the stuffing tubes into the hull with the usual mix of epoxy and cotton "dust"

I also CNC'd a little support out of CF to hold stuffing tubes steady on the motor side since its highly recommended to do so.

Notice how well the flex cable lines up through the hole of the motor mount. This is what we like to see.



and this is how we align the stuffing tube to the motor mount while the epoxy cures.



BTW Does anyone know which font is used for the official HPR 115 text ?

A. Its not a font ... its and EPS drawing!

Hello All,

I had a recent comment on the blog for an update. Its not that I have been forgetting to update the blog, but actually I have not made much progress lately since I have been doing some other things. I am basically at the stage where I need to glue the stuffing tubes in place. Here are some pictures of the jig I have made to make sure that the motors are nicely aligned with the stuffing tubes when I glue them in place. The also is sets the distance of the ends of the stuffing tubes from the motor based on my hubs. There will be about a 4-5mm gap between the stuffing tube and hub; from my understanding it should NOT be any more than this.





At the transom the stuffing tubes extend about 5mm into the Arneson drives, I don't see how it could be more.

Slooooooow

Sorry, progress is going a little slow these days as I have been side tracked on some other projects. I have however made a little progress by gluing both the motor bulkheads in place.

In order to get the alignment correct I made a small template I could attach to the bulkhead as if it was the motor through which I could pass the stuffing tube so that I could get the bulkhead aligned correctly.

The pictures tell the story I hope.





The bulkhead was glued on one side (side facing bow) with an epoxy resin mix and cotton flakes. When this was dry I removed the shaft and template and laminated the backside of the bulkhead with resin and a CF cloth in strips of about 1cm wide.




I then repeated the process for the second bulkhead.

Motors are here

My Lehner 1940/8's finally arrived so now I can continue the build. Motors are fresh from the factory dated 08/2008 :-)



So the first thing I wanted to do was get a feel for the layout of the batteries and motor with regards to the optimal CG of the boat which according the Hanspeter is 31.5cm from the transom of the sponson. Trying to keep my Lipo's as close to the CG point as possible (if the motors are too far back then you need to move the batteries forward and away from the CG point) puts the bulkhead for the motors at around 9.8cm from the rear flange of the top cover opening.

Note: my bulkheads are the ones Hanspeter sells

Next I prepared the stuffing tubes to give them a bit of an angle so they would mate nicely with the motors's axel and the hole in the sponson for the drives; of course the less angle the less fricition. To give you an idea of the angle I am using you can look at the following picture. DON'T make more than ONE bend. For a brass tube you can bend by hand gently, make sure to have the tefflon liner inserted in the tube.

My stuffing tubes are made from standard 8mm brass tubing into which I will insert some teflon tubing followed by the flexi-cable.



I imagine there are several ways of going about this and placing the angle in a different spot (maybe using two bends instead of one... NOT!!) or making the bend more progressive but this is what I came up with. Please comment of you have a better method or suggestion. The propeller shaft side of the stuffing tube can stick out about 1cm from the transom of you are using the HPR Arneson drives.

The bend in the stuffing tube is at an exact angle so that it meets squarely with the axel of the motor and are exactly inline with the propeller shafts at the transom (this is important), a bit of trial and error is needed here and of course also depend on the distance of the motor bulkhead from the transom.

The final result loosley fitted looks something like this.



If you cut the stuffing tube before hand leave enough length so that it sticks through the motor mount as we will use this for alignment in the gluing phase later on.

Once you have everything fitting nicely for both starboard and port motors you can glue the mounts into the hull.

I will cover this process off tomorrow.

Work of art

While I am waiting for my motors for my HPR 115, which I have heard are now on their way from Germany, I decided to side track a little and build my Duzi Nova R5 helicopter.

What a work of art, just like the HPR 115!!

I let you check out the pictures, need I say more.