German ER90 testing

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nitro
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German ER90 testing

Post by nitro » Mon Oct 14, 2013 12:52 am

Had some fun testing my ER90 last week.Took the Pulse Jet to Kukerin country car festival and while a V8 was doing a burn out started the ER90 up to get lots of people come over and want to know what it was.It only put out 9lbs thrust with the 10 & 13 thal reeds in so took out the 10 thal reed & left just the 13 thal reed in to get 12 lbs thrust with just Kerosene fuel.with 40% Gasoline added it started a bit faster & got 13lbs thrust.The reeds last longer with a 2 stroke mix of 40-1 also.I tried adding different length PVC pipes to the nose cone and found it only ether ran out of tune snapping reeds or not running at all.Wow,A tuned intake really has a big influence on the Pulse Jet,Much like the tail pipe really.So this nose cone is already tuned for this engine.I tried lots of other reed combinations to but non were as good as just the one 12-13 thal reed .Any thiner & they just bent into the port .Not evan :D getting hot.Still looking for ways to get more thrust out of this Pulse Jet Static.

nitro
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Re: German ER90 testing

Post by nitro » Tue Oct 15, 2013 12:26 pm

Ran the ER90 today & had another 13 thal reed snap at the base after about 60 seconds of running at 12 Lbs thrust.I put two 9 Thal reeds of the same size together next and ran this for three minutes at the same thrust but in the end they snapped to bits mostly at the tips.

nitro
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Re: German ER90 testing

Post by nitro » Thu Oct 17, 2013 12:56 pm

Cut 12 15mls deep slots in the reed valve backing plate today to lesson the shock wave blast & help stop the 12-13 thal reeds snaping off & let air come in though the centre more.After 3L of fuel was used one reed napped off at the base.Everything looks still perfect otherwise.Must remenber I am using a steel reed face plate I made myself & use a Honda weed blower to help keep cool .Not as good as 350KPH flying on a INFERNO RC Plane.Ran 12.5lbs thrust & glowed red all the time.Reed was not brand new ether.Second time used.
All in all everything still looks perfect.Evan cleaner now.But reeds still snap in the end.

nitro
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Re: German ER90 testing

Post by nitro » Fri Oct 18, 2013 2:34 pm

Put a washer behind the reed valve today to lesson the bending & therefor snapping reed valves.Worked but what a odd way it ran this time.Ran from 8LBs thrust up to 11lbs then it would go into overdrive dropping in revs & thrust ,about 2lbs.Would blow more unburnt flames out the tail pipe to.Sounded like a Harley.

nitro
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Re: German ER90 testing

Post by nitro » Wed Oct 23, 2013 2:25 pm

I finally filed each curve on the backing plate to get the .3mm reed valves to use the hole butterfly for bending then hack sawed 12 long slots & 12 short into the backing plate to allow faster reed movement,air into the chamber & less shock wave hammer at the beginning of each reed.And finally I try-ed fuel of 5,10,20,& 30% Gasoline & the rest Kerosene & 50 to 1 two stroke mix.All were about the same.About 12lbs thrust static & all started easy.Throttles well from 8 to 12 lbs thrust.Butter fly valves are progressive and help throttling.I think a better reed valve set up could give more thrust still.In the end reeds die from mettle fatigue & snap.Bugger.Wish I had a wind tunel for better testing now.Time to fly a plane with it perhaps.

nitro
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Re: German ER90 testing

Post by nitro » Wed Oct 30, 2013 1:58 pm

I stuck a fuel line 2-3in up the back end of the ER90 on my berth day & got a extra 1 to 1.5lbs thrust.Water did nothing but vapourise well.Metho & Water together was no good ether.Kerosene worked.Bit of a afterburner effect.took about 800mls a minute to do it

nitro
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Re: German ER90 testing

Post by nitro » Sun Nov 10, 2013 1:13 pm

What a jump in performance & fun.I found a way to improve my injector so much & improve the backing plate shape to soot the .3mm reed valve that my last runs static went evan better 3Lbs to 13.25 LBs thrust on just Kero & 50 to 1 oil mix with everything still looking brand new after 2 letters were used.Ran smooth all the way up to 13.25lbs and if you give it a bit to much fuel it just starts to loose thrust & not just stop.I dont know how long before a reed fails but if it runs this way on a RC plane for just one flight I will be loving this Pulse Jet forever.I really want throttling like this to work up in the air.Look up lomasck & the one with music at the start was my best Pulse Jet combination.
PS: Never give up trying out new & silly ideas on Pulse Jets.This is still a Very new sport.

nitro
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Re: German ER90 testing

Post by nitro » Wed Apr 02, 2014 12:13 pm

Ran the Old ER90 at 12.5lbs today then 14.5lbs with Afterburner then 17lbs with a 30hp Sneeky Peek Nos kit Then 18.5lbs all up.I ran a new ER90 & found it better at 13.5 static. :D

nitro
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Re: German ER90 testing

Post by nitro » Thu Dec 18, 2014 2:29 pm

Last ER 90 test I had 16lbs Static Thrust ( Fuel was 60% Kero & 40% shellite.17lbs with afterburner.I have the reed valves breathing better now & better is on the way.Last Nitrous test was on a 14lbs thrust set up topping out at 20 lbs with the nos but it used a 2lbs bottle in 1.5 minutes.

nitro
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Re: German ER90 testing

Post by nitro » Thu Dec 25, 2014 2:24 am

The er 90 is up to 16 lbs static now.Reed valves backing plate & fuel spray the reason.Not tested on a plane yet.Throttles back to 10lbs perfect,starts perfect & the reeds are lasting longer also.Thats like 5.3lbs static for a Hobbyking pj.

nitro
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Re: German ER90 testing

Post by nitro » Sat Jan 24, 2015 1:13 pm

God Dam 50lbs fish scales were 2lbs over reading.I put the 15lbs scales back on I did some more reed valve testing and found a rock solid Lbs of 15lbs at best with no ram are on the new er90 PJ & no afterburner. 13.5lbs was with a 200kph air flow leaf blower aimed at it.100% Kerosene was best on this 30+ deg day. The reeds I found best are .3mm ,80.5D with holes cut as big as possible to soot small 68D , .2mm reeds.The side wall of the big is 2.5mm & the small are trimmed to keep a 1mm overlap. When the Shock Wave Vacuum arrives at the reeds the small .2 reeds open first followed by the big .3 mm reeds second.Rad Valves on MX Bikes use this idea & it was tried on the V1 in WW2 also but Argus reeds did not need them.Starting is easier and it throttles back to 8lbs with no problems.I tried lots of reeds with holes in them evan had 5 reeds together in one 13.5lbs run.All had holes but for the last reed.As thrust was no more and starting as harder I did not bother with it.Reeds may have lasted longer mind you.All this is just bench runs and as of yet no testing in flight.I have the spark plug right up front in the fuel spray out of all combution heat and use a tiny Nitro spark plug that glows red when the car can coil powers it & starting is always perfect like this.

nitro
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Re: German ER90 testing

Post by nitro » Mon Jul 11, 2016 1:57 pm

Just lately I put my Control Line Pulse Jets away to look at improving my ER90 PJ.I had got some Blue Spring Steel Reeds Cut by Aqua Jet in Perth .I was told the SS reeds I had in it were Lazer Cut & the Blue Spring Steel would not like that as they are more heat sensitive.The Water cutting worked OK but not as sharp as Laser.More costly also but so what as its just a test run idea.I got 3 reeds to cut all different shapes & thicknesses.All done like the RAD Valve idea used in MX 2 stroke engines.When the Vacuum Shock wave arrives at the reed valves the first thin small reed opens first then the 8 thal middle reed then the big 10 thal reed last.Both the Big 10 & Medium 8 thal have big holes cut in the middle area.The last 6 thal covers the holes.Argus reeds would be better if you can build them but this idea comes next.I used Stainless Steel reeds first time & found they lose shape easy as they are softer than blue spring steel.The SS last ages & resist heat better.Last week I tested the ER90 with my new thinner Blue Spring RAD Valve cut & results were this. Starting was harder than a two reed set up but once going thrust went up to 16 lbs static with a New ER 90 used.With the Leaf blower running flat out at it 14lbs was best.The blunt intake shape of the new er90 makes more wind drag but more static thrust than the old design.It ran till 2 L of Kero was used then reeds failed.With the er90 running red hot you get radiation heat pumping back into the reeds were if it was on a plate at 400kph the radiation heat would be mostly gone.All 3 reeds were starting to chip and had some heat color on them.Testing was at a altitude of 250 Meters on this day.I still need to Test fly to see if reeds last but that,s still a Pipe Dream for me.My fuel injector is my own design & sprays at about 140 deg towards the reeds .The backing plate has slots cut in it to let air through also.On Control Line PJs cutting the backing plate lost thrust but with this model it seems to be working OK.The fuel spraying into it protects from the heat.

nitro
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Re: German ER90 testing

Post by nitro » Fri Sep 23, 2016 1:01 pm

After Having got reeds cut again results are perfect now.Three reeds.Big is 10 Thal Blue Spring Steel.Medium is 8 & small is also.Big & Small have holes in them .The 6 was hard to start and may have been no good in flight.I think a two reed set up is worth trying also both in 10 Thal blue Spring Steel.Anyway the set up I have now is 14lbs on the New er90 with leaf blower on and 16 lbs at best no blower on it.I stopped using the 90% Kero mix because of cost & now run about 20% Diesel & Petrol.The Diesel is a Lubricant for the fuel pump & helps protect the reeds.Starting is fast & runs cleaner now .I had a 10 thal bace plate water cut to protect the Aluminium face plate when reed valves snap or chip.It works perfect.No need for a steel heavy face plate.I did remove the Conic Ring ( Flame Holder ) and it ran shit.I did try some different designs & they ran shit to so back in with the standard one .I got 10 minutes static run time out of my last Static test run.All up now I am Very happy with this ER90 & nothing more I can do to it.The Fuel injector was the hardest part to make & I did make a Facebook site ( called Pulse Jet Engines) just to put photos out there for others to look at.As for the afterburner it does not help much now.

nitro
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Re: German ER90 testing

Post by nitro » Thu Nov 03, 2016 12:55 pm

I finally found the perfect Reed valve set up for the ER90 Pulse Jet.Perfect fuel injector & backing plate.Static Thrust is 16 lbs & the reeds Still look new after 20 minutes of run time.That was 8 L of 20% Diesel & 80% Kerosene fuel mix.Starts fast & easy,Has some throttle use also. https://www.youtube.com/watch?v=W6dV9g8 ... load_owner

Mike Everman
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Re: German ER90 testing

Post by Mike Everman » Sun Apr 23, 2017 1:05 am

Just got around to watching these tests. Nice rig, and great work!
Mike
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