Calculating top speed on ice...

[milisavljevic]

Hejsan Anders!

Joe ("GRIM") built his Thunderchine from mild steel and kindly took my advice to paint his engine black
with high temperature paint (eg., stove or oven paint, "BBQ" paint, etc.). Joe also has his own "recipe"
based on the celebrated WD-40. Send Joe a PM if you want information about his "hemliga brand sås".

There are two (2) points to be made: [1] keeping water + water-soluble salts away from the metal; and
[2] keeping the steel cooler; ie., black paints / treatments increase the emissivity of the metal surface.

My advice is to wear gloves when handing the steel and to thoroughly clean the subassemblies and duct
after each welding operation, and then paint all inner / outer surfaces. This will give maximum lifetime.

If you can do these things, then a mild steel Thunderchine may last for years. Just take good care of it!

Cheers,
M.

[Johansson]

That sounds great, I´ll ask him how he has done when the engine is ready for welding. Perhaps a mild steel engine would be enough, it will show how much damage it has taken after the testing has been done.

I´ll start with building the cone forming tool GRIM showed it the video, for the larger cones I can use the rollers back home in the village but the smaller cones and the intakes I will have to form by hand.

[GRIM]

Hi All
My recipe is no secret, I have just found that spraying with WD40 Prior to running mild steel engines causes the steel to form a black oxide that appears to resist rusting ,
Further applications after running certainly doesn’t hurt either ,

I agree with M, re finger prints etc, isopropyl aclohol is very good for cleaning steel of grease etc ,

The stove paint I used is all burned off now , you can see in the photo of the front mount previously posted that the cc is all white colored , that’s the burned up paint ,
I have since wire brushed the white stuff off and applied normal engine oil to protect the steel for the winter and it has gone all black again ,

I am not saying dont paint it , but it doesnt last long ,

Judging from my recent runs of this engine, the only part that gets up to a temperature that causes significant blistering of the steel is about 6"of the cone immediately after the cc transition, and to a lesser extent the cc itself , I would expect a 1mm mild steel engine to last quite long enough for your testing and ice runs,

I have been following this thread with great interest ,
The kick idea is great , I especially like the steering , should be good for speed ,
we know the engine will deliver the goods,
I see your biggest challenge will be fuelling,

At them low temperatures Propane will be useless, I saw your comments re; a small gasoline engine and a pump , that should work and not be too heavy , but I feel it is just unfortunate to have to use "moving parts" to get an engine with no moving parts to run ,

I have been pressurizing my fuel with propane , I am thinking of using CO2 instead , maybe some modified paintball stuff , will let you know how I get on ,

Great project best of luck

G

[Jutte]

Just and idea to throw in the ring .Been reading up on the
infamous V1 and it's fuel system.A gas pressurised fuel
fuel system for an ice run might work ...

[Johansson]

Propane is out of the question because of the temperatures we will race in, at that time of year the temps could drop as low as -25C so the fuel system must be rock solid and preferably produce full fuel pressure from start to finish. That is why I think that a 2-stroke engine powering a gear pump will be the best choice even though it will complicate the engine somewhat.

My friend thinks that a 12v fuel pump will be enough for the short run so I´ll try both of the fuelling systems to find out which one is the best one. I still believe that a IC-powered pump is the best since there is no battery that can run out of power or shake to pieces during the run, if I am wrong I get to buy both of us some beer so this is a win-win situation...

The WD40 treatment is interesting, if it could keep the engine from rusting it would be great. Stainless is pretty expensive here in Sweden so if we can build our engines from mild steel we will have more cash to buy food and beer at the race.

[Johansson]

We started building the engine today. Every part is cut out and trimmed to size, a GRIM-style roller is made and bolted onto the work bench and three cones are rolled successfully without any problems. A couple of hours more and the cones are ready for welding, great fun!

[weldion]

I'm totally new to this forum. I'm the one who'll work together with Johansson at the Thunderchine projekt. I will build an "Isjakt" with two Thunderchine engines mounted at the back of my construction. I'm sure it will be interesting and I guess also a bit frightening. Frightening in thinking of that I will be seated between two of those engines just a couple of inches over the ice.
My construction will look a bit like this http://www.isabella-iceboat.com/paubox23.jpg but without the sail and I will be seated differently, the main thinking of this construction will be the same.

[milisavljevic]

Welcome to the forum!

What a beautiful design for your isjakt! Once you get started, *please* open a new thread,
if you need advice or to show off your build photos. This should be a very exciting project!

Btw., do you want us to call you "weldion"?

Cheers,
M.

A special treat for anyone who forgot to click the link weldion provided..."Isjakt Isabella"

[milisavljevic]

.

We started building the engine today.

Woot!

M.

[weldion]

Welcome to the forum!

What a beautiful design for your isjakt! Once you get started, *please* open a new thread,
if you need advice or to show off your build photos. This should be a very exciting project!

Btw., do you want us to call you "weldion"?

Cheers,
M.

You can call me "weldion" or "Erik". If you use "weldion", I will for sure know that you are talking to me.
Yeah, a new thread for my project will be created. Have to start building first at least =)

[Johansson]

The cones are rolled now and the intakes are welded so we can flare them tomorrow. I eagerly await M´s illustration of the engine mod so I can start welding the engine together.

[milisavljevic]

Hejsan Erik!

If you use "weldion", I will for sure know that you are talking to me.

You can be sure I will not call you "W"! (If the meaning is lost on you, ask any 'merkun!)

Cheers,
M.

[milisavljevic]

Hejsan Anders!

I eagerly await M's illustration of the engine mod...

Ask and you shall receive...the dimensioned drawings are complete; I am writing up the post now.

Cheers,
M.

[milisavljevic]

Hejsan Anders!

Here are two not-to-scale dimensioned sketches of the starting fences that I want to include
in all Thunderchine builds going forward. The objective is simple: reduce cross-flow between
the opposing intakes during startup. Without the fences, starting air injected down one inlet
has a tendency to "jump the gap" between induction ports on the transition cone then escape
the other inlet. This wastes fuel and prolongs the startup process, particularly for cold metal.

Each fence is a simple 70x14 mm strip* of steel with clipped edges (eg., 45 deg, root to tip),
tack welded inside as shown. No need for exact placement, but preserve left-right symmetry.

(click to enlarge)

sc-9.1e1-transition-mods-front.png

(click to enlarge)

sc-9.1e1-transition-mods-top.png

Please note the spark plug mount is shifted forward close to the combustor-transition join.

Questions? You know where to find me!

Cheers,
M.

*If the meaning of strip is unclear: the fences are of thin steel sheet... 70 mm long x 14 mm high. Sorry!

[Johansson]

More work done today, everything is spot welded except for the combustor and the intakes which will be done later this week. What do you think M of the starting fences we´ve made, are they positioned the way they are supposed to?

What is the distance between the center of the intake flare and the exhaust cone next to it? It should have a 4 degree tilt according to the drawings but a measurement would help a lot to position the intakes correctly so the augmentors can do their magic.