|
Post by racket on Mar 30, 2020 19:31:42 GMT -5
Hi Scott
Congratulations on a successful spoolup :-)
Yep , the starter blower needs to be kept sealed against the comp housing inlet for at least several more seconds, until you hear her spool away to idle and its difficult to "unstick" the blower from the inlet .
You should be very happy with progress .............now the fun part can start .
Oh , one other thing , those turbine temps are very low , it might pay to just check they're reading correctly otherwise you max power temps could be under reading , ~400C is a normally fair jetpipe temp at lowish power setting with ~0.5 Bar P2
Congrats again on a very nice build
Cheers John
|
|
userscott
Junior Member
Joined: March 2019
Posts: 96
|
Post by userscott on Mar 31, 2020 11:01:57 GMT -5
Thanks John! What is the correct procedure for starting? I have done the following: 1) Lit the propane pilot light, low pressure propane, and warmed up the chamber. Oil pump on, no blower. 2) Turned on a small amount of kerosene. 3) Bought the blower in gently and then upped the revs of the blower and the kerosene flow until self sustaining. 4) Turned off propane and remove the blower. Is there a more optimum procedure? I will check my temperature senders. They could be in the wrong value (C or F) or something else weird, I'll double check tonight...
|
|
|
Post by turboron on Mar 31, 2020 11:57:17 GMT -5
userscott, for safety's sake add a drain and purge step before 1) to prevent a hard (explosive) start. You should have a low point drain to bleed off any kerosene pooled in the combustor case. Open the valve and run the blower to purge the case from propane and kerosene before 1). Whittle's first engine experienced a runaway start in the early days.
Thanks, Ron
|
|
|
Post by racket on Mar 31, 2020 17:01:18 GMT -5
Hi Scott
As Ron advised, make sure your combustor drain is open first .
Check that your low oil pressure/ fuel pump interlock is working by attempting to activate the fuel pump , .......turn off fuel pump
Oil pump on and pressure checked , also check that oil is coming out of turbo if possible, I generally have a short section of clear plastic tubing joining the metal drain line, then purge the combustor for a few seconds, you'll often be surprised what blows out .
Ignition ON and checked for operation if possible.
Blow some air through the engine , remove blower and as you witness the turbos rotor RPM decay add your start gas , you'll hear an ignition "pop" .
Reapply "idling" blower and firmly seal against comp housing inlet , you'll need all the blower output going through the engine .
Increase both start gas and blower speed and immediately activate fuel pump and start SLOWLY adding the liquid fuel , there is no need to warm up your combustor as it doesn't have evap tubes, adjust fuel delivery ramp up to prevent flames exiting the engine
As the main fuel ignites keep blower at full power until you see at least 5 PSI on your P2 gauge .
Disengage blower and turn off ignition and start gas , close combustor drain .
Check all pressures and temperatures are within specs .
LOL......I think thats all thats required , don't be worried if you forget to turn off the gas , ignition or drain closing , we've all been guilty of that at least a few times ;-)
All the best with the next few test runs , it'll soon become familiar .
Cheers John
|
|
userscott
Junior Member
Joined: March 2019
Posts: 96
|
Post by userscott on Apr 7, 2020 20:13:33 GMT -5
userscott, for safety's sake add a drain and purge step before 1) to prevent a hard (explosive) start. You should have a low point drain to bleed off any kerosene pooled in the combustor case. Open the valve and run the blower to purge the case from propane and kerosene before 1). Whittle's first engine experienced a runaway start in the early days. Thanks, Ron Hi Ron, I have thankfully got a drain fitted and will definitely ensure a drain and purge is included in each start cycle! Ron, John, All, Many thanks for your advice and guidance. I'll incorporate that into my processes for starting it. Since the start, I've replaced the oil feed line, it's quite large but was far easier to obtain the parts and a bit of extra capacity shouldn't hurt it. Thankfully this has solved all my leaks! An onboard propane tank has been fitted, a bit of a novelty really but it seems to work. I've replaced the coil with an AGM type, and it sparks like hell so I'm happy with that! I don't have a P2 pressure gauge so I'll add one as soon as possible... Unfortunately due to the current situation with regards the pandemic, the opportunity to test the train anywhere is a firm no. Accordingly today, it was packaged up on a pallet and placed into storage. I'll work on designing the AB over the coming weeks but I did need to clear some space in the workshop, so for now - she's out the building and locked away... I guess that's the end of this build, until all this is over and we can play with her on a train track!
|
|
|
Post by turboron on Apr 7, 2020 20:22:27 GMT -5
userscott, Wow. I feel your pain as Bill Clinton would say. After all your hard work it sucks to have to store it without a run.
Thanks, Ron
|
|
userscott
Junior Member
Joined: March 2019
Posts: 96
|
Post by userscott on Jun 30, 2020 7:07:08 GMT -5
Ello chaps! First time back since start of April. Hope everybody is keeping well? As you might expect she was living under a blanket for the last 3 months, but I dragged her out a few days ago and made a start on the afterburner. The unit is designed to Richard Staveleys plans (Thanks Richard!) and scaled accordingly. Are people generally using a second fuel pump for the afterburner or Tee'ing from the main pump for these things? I have provision for a second outlet on the tank..
|
|
slittlewing
Senior Member
Joined: November 2017
Posts: 458
|
Post by slittlewing on Jun 30, 2020 7:17:43 GMT -5
Looking great.... and I am very jealous of your workshop!
Its easier to control with a second fuel pump in my opinion. The AB requires lots of fuel and is likely to pull down your engine speed if you only use one pump.
Cheers
Scott
|
|
|
Post by racket on Jun 30, 2020 16:54:20 GMT -5
yep , a seperate pump , it'll prevent complications
|
|
userscott
Junior Member
Joined: March 2019
Posts: 96
|
Post by userscott on Jul 1, 2020 17:26:36 GMT -5
Thanks chaps. Seperate pump now ordered..! Just ordering the bits now for the brackets to support the weight of the A/B. Am I missing a trick with the spark plug - IE do I really have to run a second coil and all the electronics or can I Tee off the existing one some how.... I kind of left some provision for this in the build but not enough.. doh.
|
|
slittlewing
Senior Member
Joined: November 2017
Posts: 458
|
Post by slittlewing on Jul 2, 2020 5:07:04 GMT -5
Second ignition source needed too... You cant direct the HT lead (15kv+) through a relay or parallel them together (one plug would spark and one wouldn't). Your best bet is to use one of the cheap "Voltage boosters" or spark units on ebay. They are much lighter and smaller than a coil, no frequency circuit required - just supply DC voltage and get a spark out. However you can only spark them for a short time (less than 30 seconds) otherwise they overheat!
|
|
|
Post by smithy1 on Jul 12, 2020 1:29:14 GMT -5
Thanks chaps. Seperate pump now ordered..! Just ordering the bits now for the brackets to support the weight of the A/B. Am I missing a trick with the spark plug - IE do I really have to run a second coil and all the electronics or can I Tee off the existing one some how.... I kind of left some provision for this in the build but not enough.. doh. Yep, definitely a second pump...my engine actually has 4 fuel pumps.. one high pressure pump, (1000psi+), for the engine injector itself, two Bosch 044's for the A/B feed and a separate pump for the hot streak to light the A/B...l found spark ignition for the A/B was too unreliable, the hot streak works every time. Smithy.
|
|
userscott
Junior Member
Joined: March 2019
Posts: 96
|
Post by userscott on Jul 26, 2020 10:49:48 GMT -5
Thanks chaps. Seperate pump now ordered..! Just ordering the bits now for the brackets to support the weight of the A/B. Am I missing a trick with the spark plug - IE do I really have to run a second coil and all the electronics or can I Tee off the existing one some how.... I kind of left some provision for this in the build but not enough.. doh. Yep, definitely a second pump...my engine actually has 4 fuel pumps.. one high pressure pump, (1000psi+), for the engine injector itself, two Bosch 044's for the A/B feed and a separate pump for the hot streak to light the A/B...l found spark ignition for the A/B was too unreliable, the hot streak works every time. Smithy. That sounds great Smithy. Any pics of the hot streak system? A question you might be able to answer - what is the standard method of supporting the A/B - I was going to use two M8 turnbuckles but worried about elongation. I've had a look through lots of build threads but can't find an optimum solution! I think I'll need two pipes, 500 mm long with an M8 Clevis at each end...
|
|
userscott
Junior Member
Joined: March 2019
Posts: 96
|
Post by userscott on Aug 24, 2020 18:02:17 GMT -5
|
|
Sweetenough
Veteran Member
Joined: April 2016
Posts: 121
|
Post by Sweetenough on Aug 26, 2020 2:28:10 GMT -5
Nice looking AB! Have one little suggestion, the spring around will most likely be "cooked" and loose it's spring force once you fire up the AB. Using the same design :-) Has not been a problem even with a loose spring but if I should redo the design I would have used some kind of distance piece inbetween the AB and the spring too avoid overheating the spring. Regarding "hot streak" I have used the "normal" fuel supply to the combustion chamber and operated the engine at almost to low rpm, then made a step increase of fuel too get a flame thrown thrue the turbine and igniting the AB fuel. This was all suggestions from Mobacken racing (Anders and Olov) and works quite well. You may get a flame out when operation on low rmp or it will not ignite everytime (if you are not low enough on the rpm and/or does not make a large enough fuel step). Just recently I tried spark plug ignition (have a sparkplug installed from the beginning but never had a ignition system and tried it) and it worked surprisingly well. Just made a few tests but if it continues to work this good, it will be my new prefered choise to ignite the AB. Using a regular car ignition coil with an electronic pulse generator (made by a friend, I think he sells them if you are intrested). Have been very reliable.
Kind Regards Thomas
|
|