Broken reeds? This engine breaks whole reed blocks!

[@DavidGierke-nl1dl]

As I mentioned a couple of videos ago, a dynajet model pulse jet engine's spring-steel reed valves have easily withstood 1400+deg. F temperatures while running on 90% nitromethane fuel (control-line speed; 200+ mph). The reeds have a pedal (like a daisy) configuration and have a relatively high aspect ratio; they cover multiple circumferential ports in an aluminum induction head, whose opening allows for a surprisingly good flow-rate. These reed valves are still available and can be easily adapted to your engine configuration. You can find multiple references to the Dynajet engine on the Google search engine. If you decide that you want to try these valves-I have them (new) and will supply them to your project free of charge. By-the-way a simple disc-retainer prevents the reed petals from over-opening.

[@ferrumignis]

The problem with spring steel reed valves is if/when they break they tend to cause a lot of damage.

[@jeffreywagner1084]

I agree this is a good option . What material are they do you know? I would think some S7 might be a good choice. If you can find out what material they are and what hardness they are made to would be interesting to know. I am curious to know what metal maintains its hardness at those temps. The valves may not get that hot in a pulse jet as they are constantly having cool air drawn across them but I could be talking out my ass on this as I have no practical experience with them. Be interesting to know though!.. Cool Stuff... ** I am an M.E. / Journeyman Machinist and always looking to learn something new **

[@paradiselost9946]

the average common garden grade air compressor runs spring steel valves for... iunno, mines fifty years old... reeds dont flow. regardless of what the charts say. really simple. hold two sheets of paper together then blow between them... what happens?

[@gadgetdeez7069]

The problem is they run full send at around 60 psi (4 bar).. he's trying to make them live in a situation exposed to upward of 70 bar (nearly 1000 psi).. it's not going to live and needs a significant design change.

[@paradiselost9946]

@@gadgetdeez7069 yep, plain old simple poppet valves. nothing else will have the flow, the seal, and the pressure capability..

[@HueMongussD]

Look at the reed valve design used on 47cc pocket bikes. They use a curved stop block that keeps the reeds from over extending and breaking when they open. I fabricated some for use on my motorized bike. Haven't experienced reed failure since the addition of the mod. I posted this comment under another video but see it's more applicable to this one. ✌️

[@timbahlert62]

Danke LANGTUNIG!!! Super Geil das ihr 2SS Sponsort! Danke auch an JEDEN anderen der die "Reise" ermöglicht! Vielen Dank!!!!!

[@Momfasa]

Rausergeizer knapfkopf????

[@klappspaten3012]

Danke an Jan von Lang tuning

[@GlekkeMatrak]

"Manhood threatening music" hahaha 😅. Love your sense of humour!

[@BeamBinge]

Good luck and greetings from the netherlands!

[@craigpierce7996]

Can you hear it?? Drum valve, drum valve!! Seriously, I think that's the best solution in your boosted application. Especially the air volume level on this motor. It's pretty close now...

[@pfrischknecht]

I love the music... if it matters. I think your "cinematography" is more immersive with the music. But alas. ALWAYS happy to see you working on your projects.

[@Nico_0900]

Langtuning used to work 2 km away from me. What a coincidence 😂.

[@TheLtVoss]

Nice I was also quite happy too hear that one of my Favorit yt gets sponsort by a kinda local company with good Reputation

[@RestoMog]

I very much appreciate your choice in music, ignore the haters.

[@PolygonSwan]

Me too it's part of reason I stayed.

[@mrln247]

You don't see many people walking out of a cinema "because they put music on the film"

[@Decayrate-of-Ravn-Rike]

Whatever music you want to use, use it. It's your channel. Usually the most annoying thing (for me) is how KZbinrs tend not to be aware of "sound levels", although it sorts itself out in the end.

[@marlobreding7402]

I love the Blues music you play 😅

[@Billskins4dayz]

this 👆had no issue with the music people can use closed caption it there for use

[@slateslavens]

Yep. I always look forward to hearing what kind of music gets picked for the video. It adds to the story.

[@at_3831]

Made my day seeing this video posted thank you for the hard work!

[@david929190]

A 1976 CCW 440 engine from a John Deere Liquifire I worked on has aluminum reed cases and steel reeds with steel plates for limiting the reed travel. More models and years of snowmobile engine came with aluminum reed cases. They also are generally rubberized to create a very good seel and are large for the large displacement engines snowmobiles have. Cheap as well.

[@coltmiller5204]

I'm wondering if it would be a good idea to put a burst disk, similar to the ones on supercharged engines, in the crankcase to prevent extensive engine damage when it backfires.

[@vilivuorinen8096]

If you still want to bother with fiber reeds, machining an extra support into the cage at the middle of the reed is could help with the cracking by reducing the unsupported area. That way you could run custom metal cages still with the fiber reeds.

[@2988ian]

You could remove the dump valve and just fit an adjustable blow off valve instead. This is how I run my supercharged MGB, valve bleeds off excess pressure in the event of backfiring.

[@davidcabrera1939]

Music or no music, I'm invested

[@rct2]

What we would do back in the day when we would mod our dt50's, we would often use reed cages from 125cc bike's. Bit of fitting required but they held up well for us.

[@JamesBalazs]

Is it currently using reed valves and cages from a 50cc? From a turbo 4 stroke car background, I know running 1.5-2bar of boost is increasing the amount of air pumped into the engine by about the same (+150-200% optimistically assuming that's relative pressure) So running a reed valve from a 50cc NA engine on one that is actually pumping similar air to a 125cc-150cc seems like it would be a restriction too, not just a case of a weaker cage?

[@rct2]

@@JamesBalazs just what you said

[@mariamaniscalco7413]

So how did the dt run w the 125 reeds in there, did u change the pipe n carb w the big air box? Then that would be a really fast dt50.!

[@rct2]

@@mariamaniscalco7413 at the time quite well if I remember it right. 65cc big bore kits, even fitting the 125 top end to a 50 bottom. Worked but didn't last to long.

[@flakey7832]

I think you should just use whatever music you want man, it's your channel after all. Super excited for this engine, can't wait to see it strapped to a chassis

[@cjcantrell80]

After having watched the early stages of this build, this is exciting progress for some sustainable pulls and testing. I eagerly await the numbers this bold concept can produce.

[@baothiletran-ef8zn]

Thank you! I love the work you are doing and sharing your amazing videos on Gan jing world. Welcome to the new world!

[@TheRedmohawk]

Put a pressure sensor on the Brake line will give you an indication of braking force , it will not be accurate but will give you a good base line for how hard your braking . Replacing the hand leaver with a longer unit (Screw/zip tie a longer arm) then use a spring to load the arm at a set distance will help , assuming pad wear is minimal for testing.

[@noenlunde7028]

Its a port timing problem, i suggest you make the exhaust port open 1 degree earlier, maybe you eliminate the backfire problem.

[@ariel2t]

Yes, is a port timing problem. But need. Several degree earlier of exhaust. Is better if you use regular time-area parameters for exhaust blow-down. That will give no pressure from exhaust gases to the reeds. And maybe a little Vacuum.

[@thebrain9384]

In otherwords, it should run and breathe at a specific rpm.

[@noenlunde7028]

@@ariel2t Maybe, or some degree later at the inlet port

[@fastdadd1958]

Wow once you get a pipe it is gonna breathe by the look of the tubing you used. That was a lot of back pressure, great work, good luck and break a record!

[@Soshstar999]

It's sounds like it's all coming together pretty well, keep up the good work, and you will make it

[@chyrayoung4790]

I wish I knew you IRL. You seem like you would make a good friend. I like you and your brain! Unfortunately I live in the US...

[@bostonbikebits6539]

Brilliant to hear you have got a sponsor for Bonneville, really look forward to seeing how it goes.

[@seanmccarthy7760]

I like what you are doing ! maybe a dumb question but, why reeds AND the rotary vavle ? seems to me, a rotary valve would be ideal, despite the limited Int/Exh timing. I wonder what Kevin Cameron thinks ?

[@stephenfrancisvoros382]

Great to hear that little motor singing again. Take a look at the old school Yamaha RT360 or DT250 reed block's, steel reeds, over engineered and made to last.

[@roos7961]

A off the shelf option for the cage is the Boyesen Rad Valve as its fully metal , you could again get a Cr85 one and upgrade it to metal reeds when you liked ..

[@allthehandlesweretaken]

i think you should go for a larger reed cage. and steel reeds. in a boosted engine you should be able to overcome the larger size. but also since it's larger. there should be less stress on each reed. thus making it more durable. and with stiff enough reeds. it should be able to run on lower rpm to

[@wadesta1986]

I'm assuming your misfiring at high RPM is related to your plug gap. 2 bar of charge is going to be really dense and quite difficult for the spark to penetrate. It.might just be a matter of closing your plug gap to like 0.8mm or even less.

[@MrZarnach]

I really liked light jazz background music

[@Ratkill]

Is it possible to add a sparse support grid under the reed, or would that create too much extra turbulence

[@OddsandEndsMachining]

I’m thinking maybe steel reeds of the thickness you need won’t be able to work at the desired rpm, usually that’s why with high performance they move to composite material. Would a disc valve on either side driven by one shaft work? Maybe using a small bevel drive off the crank or off an idler pulley.

[@mmazz30]

I've used thin paint scrapers (spring steel) to make reed petals.

[@mikeford5106]

The mid 70's yamaha 250/350 had aluminium reed blocks with stainless steel reeds, and they were reliable .

[@jeffreywagner1084]

Try TITANIUM REEDS but don't use CP Ti. ( commerically pure). You want something like 6-4 or 6-2-4-2. Something with some spring properties in it. Ti is very resistant to breaking. There is also several spring steels that would work great but they would require either you buy the material with a proper heat treat on it and then have them cut out by a shop with an edm or waterjet or you buy the material soft and then find a PROFESSIONAL heat treating outfit to heat treat them for you after they are done. There is no garage shop dunk it in a can of oil heat treat methodology when the risk of damage is so high if they get it wrong. Titanium could be machined as it would not need to be as hard as spring steel would need to be to make it strong enough. I mentioned 6-4 and 6-2-4-2 but do a little research as there is no doubt better alloys available these days. But Ti will not break unless something catastrophic occurs. But do NOT use CP Ti. It is too soft and not springy enough.

[@warwickpratt3032]

Maybe something is hitting your reed block or you have huge vibrations in the engine for it to break. You could rout a grove in the reed block and run an o ring in the groove and mounting bolts (retaining compound to lock the bolts) to help reduce vibration. Reed and carby would float then.

[@finnsk3]

I forgot about backfire protection. Makes sense now. I would run a hose from between the carb and supercharger to the top of the dump valve so at part throttle the vacuum will help open the valve so it vents at part throttle to reduce intake temps when not at WOT. Might not be worth the effort but if it’s easy to add, worth a try. It’s looking much better with the bleed valve.

[@HulluJanne]

I would try RVS Technology on the rotary valve. Should reduce the friction quite significantly!

[@1986muscle]

Enjoy this channel so much I click like before I even watch an episode

[@daviddavis325]

Wonder if pieces of reed are what tear the exhaust ducting at about 7:44

[@2STROKESTUFFING]

I think it is.

[@dustinjanes]

Use udahome (spelling) steel. Same material that shock shims are made from. A bridge in the center that is solid top to bottom. Makes two compartments.

[@xibidit]

maybe you should have the brake caliper at the bottom of the disc, and submerged in water. I dont exactly know what fading have for effect on your particular setup, but if it has an effect, power figues probably would be obscured and all over the place, right? water would both cool the disc, brake pads and your face when splashing around this summer =)

[@roboman2444]

Could also just have a small aquarium pump dribble water onto the pads/disk if you don't want anything submerged.

[@50und524]

If you intend on staying with the reed valves, I seriously think you need more blowdown area, it seems cylinder pressure is still way too high when transfers open, hence the broken reed cages.

[@gadgetdeez7069]

Blowdown doesnt matter. At the end of the day you're creating a bandaid of increasing blowdown to save the reeds which lowers cylinder pressures and significantly reduces power output, something that he'll just blow right past again by changing sc pulley ratios and be right back where he started. Problem is he has the intake ports /reeds exposed to cylinder pressure. When combustion happens, they take the brunt of that. Expect nearly 1000psi or more on those reeds with boost and 8:1 cr. (Which i think he is WAYYY higher cr than that).. they arent going to live. He needs a barrel valve or a poppet valve to do what he's trying to do.

[@Tunerfreak99]

Hey Alex, have you thought about a burst plate? They use them in some supercharged drag cars in case of backfires. It might be worth looking into, lot more compact and simple

[@thebrain9384]

I'd suggest a redesign of the piston top, replacement of intake and exhaust ports, no reedvalves at all.

[@thomascaldwell184]

"Manhood threatening music?" Dude, I always love your music choices. Maybe that says something about my manhood...

[@BladSG]

Thank you for no music, i prefer that

[@Detsiboy99]

Blingfactory makes aluminium reedgages, and steel reeds will be good way to go. It have enought flow to operate with them👌

[@markrutlidge5427]

Do you know what the crank case pressure is, you might need a smaller supercharger. As it is your cc pressure is 3 times atmosphere, no wonder the reeds keep keep on breaking.

[@delcowizzid]

Hes trying to hold in 800 plus psi of combustion pressure it's not the crankcase pressure that's the issue

[@jnljnl8485]

Would a twingle setup be better for the boost since it's not possible for it to just blow the boost out of the exhaust? It would limit the exhaust some with the small diameter cylinders I guess.

[@rachalhollier5679]

Get your reed cages from Taiwan,Thailand, Japan. They make the most dependable parts I know of.

[@stefandanalexandru9401]

Same thing happened here. Never had luck with vforce style reeds, too weak for serious application even just NA, tried boyesen with their normal style reed and are much better, even made more but power, it resists much more pressure they have double layer "plastic" style reeds, the only ones wich where able to resist in my 300cc 2 stroke modded engine application.

[@heatherbrown2761]

It's impossible to threaten my manhood. :P Play whatever music you want =)

[@jaakkorisku7811]

How about using the umm. I don't know the english word for it but spring steel might be the most understandable word😅 for the reed valve i mean. They might actually be that material anyways i don't know but it just crossed in my mind while drinking😅 allso just thinking how about make some tubing from that wastegate to the intake of the carburetor so it would work as bypass valve and recycle all the fumes instead blowing them outside... Sorry for my bad english😁 you'r doing great and your videos are the main reason i watch youtube🤘 never give up!!😎👊

[@gislemark79]

Make the lever for the brake longer, it will be more sensitive and easier to dial in.

[@Viktor_VVT-I]

How do you like the idea of creating a 4-stroke 50 cc engine with 4 valves and turbo boost?I think the power will be about 7 horsepower

[@timsgaf]

can you double the reeds up, like a car leaf-spring. thanks.

[@mistermacgray]

First! Okay now to watch it and be back with any comments. Keep up the excellent work! You have done the final inspiration to buy a amr400 and custob mount to a 2 stroke I have for more looks than performance, project will be a cpuple years out before i start it but planning now will be key.

[@TheNumbers400]

How about trying to double up on the reeds. If they are "tuned" to work without boost, boost might just need a stack of two, or three depending of boost levels. An easy thing to try out.

[@tristanyseult]

Just thinking laterally, if this is for a land speed record ,could you use a compressed air cylinder instead of supercharging. If it were fiberglass it would be light. If it were aluminium it could be incorporated into the bikes frame. I think there might have been some experimentation in drag racing where weight is important , but speed records not so much so.

[@thebrain9384]

Use a sparkplug similar to rotary engines, use an electric blower,turbo design, with electronic control of boost.

[@einhase6924]

Maybe a reed cage with more support for the petals than only a bridge, will make the carbon petals possible. I think it is worth trying to make the Carbon petals work, but if you use the metal ones I would check on them every few minutes of runtime.

[@AntiVaganza]

I think he did a few years back but I might be wrong

[@jaevlakul]

highlight of the week

[@Rosteripulla]

Would it be possible to run a mesh after the reeds to prevent fragments from entering the engine if you switch to metal reeds?

[@andhag]

Those notches in the one-piece reeds look like perfect stress risers. I wonder why they are designed like that.

[@benjaminritter5286]

Maybe a solution for the reeds is also to make them diagonal with the raster of the carbon fibre . could change a lot

[@Chris719p]

Hi Alex, outboard motor engines use reed valves

[@peterpyzer]

Endlich ein neues Video , greetz From Germania

[@gps4l184]

I am wondering what the best metal would be. Spring steel ?

[@jongonegone1262]

BRUTE FORCE, HE WASN'T KIDDING !!

[@Angus762]

I would try steel reed valves, or shim stock? Best wishes.

[@raymondo162]

3:37: Viagra.............. those engines got a lot of poke !!

[@tejdz1337]

you probably need aluminium reed cages and steel petals

[@LeObsidianCraft]

Yep, time to fire up the CNC mill!

[@spgracing6253]

To me it seems like the waste gate should be after the reed valves. You have no backfire protection with the waste gate before the reeds. The waste gate won't start relieving backfire pressure until the reeds are already broken. That's probably why they are breaking, the reeds are taking the hits from the backfires until they break. Just my thoughts.

[@NitroGnome]

Carbonfiber is bonded with resin... it is very possible that resin does not like nitromethane and alky + charge air temperatures might make own twist too...

[@TedTucholski]

Tells us about Lang tunings product and services. Thats what sponsors want.

[@jonathanward8861]

In case of a musical interlude, might I propose the theme music from 'Shaft'? Manhood up to 11 😎

[@PhotoBilly]

looking good!! so much potential

[@deancrawford2577]

I still say in my opinion this engine should be fuel injected , 2 injectors, one spraying into the crankcase and one spraying into the transfers, it may even help the reeds live longer by only having fuel on only the one side of the reed.

[@gadgetdeez7069]

I dont think 1000psi combustion pressures are a situation that any reed will ever live in. Pulse jets operate at a max of nearly 60psi.

[@deancrawford2577]

@@gadgetdeez7069 The combustion pressure should have no effect on the reeds, as the combustion should only be regulated on the top of the cylinder and timeously in the exhaust expansion chamber, when adding boost crankcase pressure is increased which in theory should aid scavenging and keep the combustion away from the bottom end. The only way I can see a crankcase with combustion pressure is if there are severe misfires. Maybe timed injection could minimize the misfires?

[@PolygonSwan]

The music is what hooked me.

[@pl7868]

The reeds are probably resonating to destruction same as the tail feathers in an airplane , talk to an aeronautical engineer they deal with that stuff and in any materials you could think of , face it they balanced the SR-71 airfoils going probably faster than your reeds

[@Orbacron]

If made from metal, then must be so sturdy that It will never break off into engine. Mabie a metal frame with much more supports, and keep the Reed material same?

[@turkeyboyjh1]

I always thought the “uniflow” design has major advantages in the power department

[@mazdamaniac4643]

I think that you're decieving yourself with the reed valves. The reeds aren't the problem, they're a symptom of another problem. There's a reason *why* you're getting backfires. I'm wondering if there's an overpressure event taking place inside the crankcase, which ends up holding the reeds open for longer than they should be. You could be experiencing a pressure wave being bounced back and forth all the way between the reeds and the supercharger, something that the wastegate can't deal with because it's too brief...until the reeds give up. Stiffer reeds isn't the answer, it'll make it worse. You need that overpressure pulse to go somewhere, so you may need more crankcase volume via a plenum chamber to even it out. We used to have similar problems on some Yamaha RD's we were tuning. The solution was to remove the balance pipe on the intakes and enlarge it quite drastically, forming a plenum chamber that bridged the seperate intakes. It still maintained intake balance, but it dramatically cut down on any rough running from unstable intake pressures. We learned the importance of critical volumes that day.

[@nfdr0kk3rz]

I wonder if with the blower you can get away with using a tesla valve instead of the reed valve arrangement, it wont flow as well but also no moving parts

[@Nico-ds9nz]

Pyrotechnik... Ist doch keine Verbrechen.... Wir werden dafür kämpfen und lassen Emotionen freien Lauf...

[@nicklaslangvad]

Bring back the jazz ♥️

[@alcr6201]

Try harmonic steel reeds, maybe with supercharged engine works better

[@thebigd9989]

So much pressure 🔥

[@ph0end]

Forget the folks who complain about the music, make the content you want to make; doing that is what brought everyone here in the first place. Bring back the guitar, too. Do _you_, man. Would be cool to jam with you if we weren't so challenged by geography and a dash of crippling social anxiety haha

[@jamescharron8550]

Rotary cylinder valve

[@metrichotrods1763]

Steve Tassinari at Moto Tassinari/V Force can fix this issue. Also, the first reed valves were made of aluminum.

[@bandidol200]

So why not try a metal reed cage with composite reeds, that way if it does break you won't have the destroyed metal reeds compounding the damage? Just sayin'.

[@Bingzor1337]

Music on this channel is and has been a good blend in to the theme 👍

[@soaphelps]

had a super combat wombat 125 that had a aluminum cage with steel reeds, might have been stainless.

[@simonrechner9395]

maddox pulse jets has the reeds you need

[@jasonrailton2172]

Would a brake lever with a rachet be easier to control the dyno. Like a car handbrake lever or emergency brake lever. Ditto RestoMog's comment. 👍

[@michaelfowler8289]

You need to get ahold of carsandcameras I believe you have similar likes and not to mention they are into top speed lay down motorcycles though there's our pavement pounders I think it would be beneficial to you very beneficial😮😊😁