MJD

My Feedback: (1)

I was going to point the launch rail north at about 30 degrees elevation, in case the radio craps out as soon as it leaves the rail. At worse it will smack into a polar bear at 250 mph.

They all shake pretty good, in this case probably about like a hard mounted one-jug gassie at 9000 rpm or thereabouts. I don't think the transients are too severe, but I'll look to see what I can find on that topic. I haven't heard of radio problems in the write ups of the various pulse jet RC projects I've read about. Naturally I will pad the Rx and battery very well in low durometer foam, and they will be very firmly restrained in their own compartment with no room to move about.

I do note that the MAAC turbine rules do not allow IV bag fuel tanks (d***it).. so presuming the same applies here I will have to make a fuel cell with bladder. Or I might try a clunk type fuel cell with a BVM air trap. I plan on 1 - 1.5 litres of fuel, there are BVM fuel cells available I could use. Or maybe 4 Jett 12 oz bubble-free tanks in parallel. All such problems can be overcome, just add money..

MJD

KC36330

you mean about 2000 RPM?? gassers smooth out at RPM, it's idle where they shake.

kc

MJD

My Feedback: (1)

Well, I was just taking the approx resonant frequency times 60 seconds. Okay how about like a gasser at 9000 rpm with 1/2" missing from one blade?

Ed Smith

MJD,

When you fire this project up let me know. I want to be there.

Ed S

rmenke

My Feedback: (13)

Ok: We'r trying to post some pics, follow instructions, volla?? Well, one of 4 not tooo bad, maby will loose it ?

rmenke

My Feedback: (13)

Well, here we go again, no pic in the box as its supposed to be, but pic uploads with a message. Now, how do you get a series of pics in this same box?

KC36330

I'm confused as to what it is you're trying to bring to the thread, this is about a pulse jet engine not a Jett engine.

kc

MJD

My Feedback: (1)

I spoke at length to the MAAC Jet Committee chairman last night, and in his opinion the rules for turbines apply to pulsejets, and other than that there are no additional restrictions. He was quite curious about the engines, how they function, how they are started etc., and once I explained it all to him he pretty much agreed with my opinion that one is about as hazardous as the other (turbine vs pulsejet) with the understanding that pulsejets are hideously (or wonderfully depending who you ask) loud. Her echoed one of my earlier comments by saying that they are so obscure MAAC has not likely had to worry about them much.

The safety code for turbines includes a few things:

- no IV bag tanks (prone to rupture in a prang)
- two means of shut off required (throttle command to the fuel pump plus a manual shutoff in the fuel system will do)
- externally mounted engines must not touch the ground in the event of belly landing or a retract failure, i.e. put the engine on top

The IV bag tank thing is a pisser, because it's a great way to get a lot of fuel on the CG via two compartments near the wing root. Oh well, I'll have to buy or make a 1.5 liter fuel cell and fit it in there somehow.

I'll screw an old propellor to the nose to qualify it for this forum..

balsaeater

half inch boat prop will have the least drag

Way to go

possibly next year will do pulse


The price of turbines is just toooo much

I can drive into stickville which each year gets more empty as everybody leaves the land top go live in big towns and mostly fly guerilla style set up fly and find a new spot the next week so spreading the noise print around and i can do a pulse for a lot less as even at eu prices of $6 a gal takes a lot to use up $2000 in gas prices

no chance any club can take the 150db more than 1 time a year if that
No issues to use pulse in EU generaly in the stickvile but problems noise ristricions close to habitation and pulse still very popular pre turbines and sure the tubine guys still use them occasionly


Spain big issues forest fires so lots of clubs wil have no turbines and pulse for fire risk in summer time

No issues to use bladder tanks in planes

keep us posted on this motor and might get one next year as not to many manuftuers out there

The throttle bit is unusual but not realy interesting feature for me

keep me posted on how much work to keep petals working and replacement rates or similar

What is the best way to make a wand that you know

Balsaeater

MJD

My Feedback: (1)

The manufacturer suggests making one from a piece of steel brake line - 1/4" - 3/8" - for the air tube, with a second wire beside it for high voltage, using the tubing as the ground conductor. The two are anchored in a wood block outside of the tailpipe. They show a spark plug at the end, but you could also simply make a spark gap between the HV conductor and the brake line tubing.

The throttle is mandatory, because you feed it with a turbine fuel pump with speed control. You need to be able to set the maximum flow rate to the manufacturer's specification and make this the 100% throttle setting.

I will know about reed valve life once I start using the motor regularly.

The only makers I know of for large pulsejets are Zanin in Italy and the company making this Maxjet.

MJD