reedy
Veteran Member
Joined: January 2017
Posts: 111
|
Post by reedy on Feb 15, 2017 5:35:15 GMT -5
Hi Jeff Don't think there is a leeward side as the angle is a calculated guess and can be out in any direction i would just min radius both sides as it could be wrong with making the diffusor vanes into wedges,don't know about designing diffussor,s is the 24 degree angle measured to the middle of the wedge ? do you compensate more or less for thicker vanes ? Curved vanes are supposed to be better than straight vanes and curved thin wedge shaped vanes could be better still,reading a build thread with Gerald Rutten and others, Frank turbine shown half way down. they also talk about min gap to diffusor in one of the latest designs but this is 2008 ! Sounds like it is too complicated for them so I've no chance ! can not find any resent stuff. www.modelbouwforum.nl/threads/keildiffusor-ii.71197/page-3translate to English, most makes sense.
|
|
reedy
Veteran Member
Joined: January 2017
Posts: 111
|
Post by reedy on Feb 13, 2017 6:22:20 GMT -5
Hi Jeff
looking very professional, are you adding another layer of cloth to and bottom to tie it all together. Have you done the combustor yet ? Chris
|
|
reedy
Veteran Member
Joined: January 2017
Posts: 111
|
Post by reedy on Feb 5, 2017 3:27:09 GMT -5
Hi Jeff
When you molded the intensifier did you allow for finished component thickness by packing the delrin tool,I used a bees wax sheet at work smooth on one side sticky on the other and being wax you can smooth it round compound curves.if not fitted it will tend to press on the top edge and not at the rim of the wheel.
|
|
reedy
Veteran Member
Joined: January 2017
Posts: 111
|
Post by reedy on Feb 3, 2017 19:05:12 GMT -5
Hi Jeff Would not try that .a quick Google shows It can contain between 51 to 85% ethanol does that mean it can contain up to 49% gasoline (petrol).
|
|
reedy
Veteran Member
Joined: January 2017
Posts: 111
|
Post by reedy on Feb 3, 2017 17:52:16 GMT -5
Hi Jeff
In Kurts book Model Turbines with the TK50 and KJ66 he talks about fuel,cheaper alternatives using Diesel or biodiesel with 15 to 20% petrol(gas!) or safer 20 to 30% paraffin,you could also try heating oil.Tax lower on heating oil in UK. It will depend on how good you vaporizers work to how much petrol or paraffin you add,but best to get it working right on straight paraffin or jet a1 kerosene. I think heating oil comes in different viscosity they call it 28 secound burn and 35 secound burn something about how long a ball bearing takes to fall down a tube with the oil in.(I think ! you need to check on that) Diesel £6 UK gallon. Paraffin £9 for 4lt per packed. Heating Oil £0.29 for 1lt .
I've tried the 28 sec did not seem any different than paraffin in my FD3.
|
|
reedy
Veteran Member
Joined: January 2017
Posts: 111
|
Post by reedy on Feb 3, 2017 17:15:30 GMT -5
Hi Adam Just a quick hello I'm new to the group and been posting on Jeff,s build so I thought I would stick my nose in here ! Only had a quick look back, it's looking really good,it must have been a lot of work casting. I have a artes wheel but it,s an older design, yours has the fins on the centre to help the airflow out of the bearing tube. Gerald Rutten has done a modified KJ66 diffuser, I spotted this drawing on a build thread last night when looking for his GR180. www.modelbouwforum.nl/threads/keildiffusor-ii.71197/ never did like the idea of the little vanes round the outside,seen a flow diagram from the wedges to the vanes and it did not look good. Regards Chris
|
|
reedy
Veteran Member
Joined: January 2017
Posts: 111
|
Post by reedy on Feb 3, 2017 9:52:22 GMT -5
Hi All Just a link to 1993 ! Don't know the guys but this must be the original design FD3/64 not balanced well and the vaporizer coil puffing and making the engine oscillate in rev's doubt it has 5 lb thrust.sounds more like a steam train. www.youtube.com/watch?v=bNRRaJ0Kgq8check out his other videos and watch his progress in 94 www.youtube.com/watch?v=1pTmA677rhY
|
|
reedy
Veteran Member
Joined: January 2017
Posts: 111
|
Post by reedy on Feb 2, 2017 17:24:41 GMT -5
Hi Jeff
Yeah same as kamps it's the best static method,works even better with ceramic ball races.
Plenty of people got them running but low on power and high on temps,it was the first engine most people built so tended to be built rough with big clearances. Like any engine it,s attention to detail every little detail adds up to lowering the temps.
I cheated early on and got a compressor wheel and turbine wheel off Mark Drake. It was Mark who's ideas made it work,cutting the turbine wheel at 40 degrees wider blades less angle on the tip, his combuster, and the open fronted alloy wheel of Rob's. got me to 6.5 pounds.
The first engine I flew was with the wooden wheel, turbine as book and a new combustor with walking sticks by Kurt 4.5 pounds thrust,flew in a thorpe brothers delta fighter old DF model.
The Kamps give me a lot more power most people jumped to this design when it came out and then the KJ66 was easier as most people just bought the bits compressor,turbine wheel and NGV and it was guaranteed to work well.
In a nut shell not many people flew it ,but that makes it a challenge,and it,s cheap in money but not time,like I say to people now if you want to fly a turbine just buy one,but if you want to know how they work build a FD3.
Keep going with the test running and do one or two things at a time and you will see the temps drop and power go up.
Hope I haven't put you off, yours looks great with the Heineken can that's going to be one cool looking plane nobody else has.
|
|
reedy
Veteran Member
Joined: January 2017
Posts: 111
|
Post by reedy on Feb 2, 2017 14:16:05 GMT -5
|
|
reedy
Veteran Member
Joined: January 2017
Posts: 111
|
Post by reedy on Feb 2, 2017 14:06:34 GMT -5
|
|
reedy
Veteran Member
Joined: January 2017
Posts: 111
|
Post by reedy on Feb 2, 2017 9:10:51 GMT -5
Hi Jeff
I did read though the discussion on sticks,my thoughts below. My original size fd3 with the 631 combustor has 8 walking stick shaped tubes,I had to use the walking stick shape as my NGV is conical shape as per drawing so the combustor has no back to it as per drawing.
Your sticks will vary in temp depending where the hole pattern falls,
You could use 10 straight sticks from the back as your combustor looks like kamps ,kj66 with the sq end.I would make them 1/4 dia as you could feed too much air into the premier zone as it was intended to have the coil with 5 drilled holes. if you feel that,s not enough when you push it, try doubling the large 7.5mm holes( seems a large hole) but 1/2 the size of the hole with 20 sticks.
The sticks on the fd3 are not subjected to the high temps of the kamps and kj66 they will not burn away quickly like the early wren 54 did(amazingly small combustor 1/2 size and twice the power),Think it,s due to the low pressure,Only problem Mark Drake had with the 631 in testing was when he had a blocked injector and it coked up one stick which he cleaned out fitted a new spring in the end and it was ready to go ,he only used 316 stainless.
The sticks have to match the hole pattern KJ66 started off with 6 and then went to 12 ,the more sticks the more even combustion but you have to go to smaller injectors for good starting and slow running ,I've found the kj66 combuster to be very good and happy with 6 sticks.
10 1/4 dia sticks from the back should work well with your x1.4 they will get hotter air ,stop them about where the 3mm dia(4.2 on yours ?) row of holes is, about 14mm from the front of the combustor .
I feel you would be better doing more running with your first engine, and mod it, learning curve should help with the second. More videos of engine runs this time with thumbs up.
when you had your sticks welded in did it buckle the front pressing,mine did on the first one,more scrap that's why i built a spot welder,to weld the sticks, seams,brackets for holding fuel ring,the 3 z shaped lugs for holding the front of the combustor central and patch over any holes.
Try not to weld the combustor up totally unless you are sure of it ,I had the inner welded to the front and just wired the outer using stainless wire though 6 holes 1mm in the corner then i could get at things and see the burn pattern better.
The outer combustor wrap is on the outside of the end plates because of the pressure difference lower pressure in the can,it could push in if fitted inside ,but i have done it inside as with 0.5 sheet and low pressure it,s been ok ,if using 0.25 and KJ66 stick as per book.
If the sticks getting a little too hot you will see a flaky silvery grey appearance,mine show this near the large holes they loop round brown or biscuit colour elsewhere ,the sticks are 0.5 wall.
If you are drilling a hole for the straight sticks drill under size 1mm and punch it out to size as my video on youtube it helps to strengthen the area and hold the stick.
Another long one, sorry.
P.s On gas 8-10 sticks will not make any difference so worth doing more test to reduce temp before you mod it. Did you spot the spinner on the x2 engine nylon then ally larger dia to blades and radius.
|
|
reedy
Veteran Member
Joined: January 2017
Posts: 111
|
Post by reedy on Feb 1, 2017 17:30:18 GMT -5
Hi Jeff
Been thinking about your combustor ,as I said before you want the large holes blowing in the middle of the u of the stick,10 holes ,10 sticks. Can't find any info on walking sticks fitted to the old combustor but as we know about the x2 on youtube works. After watching youtube again it's hard to tell but it looks like the tubes are long enough to loop over the 7.5mm holes,about 40mm from combuster face to inner loop of the sticks. The stick ends I would finish about 10mm from the front face in line with the 3mm holes.
I have seen a deflector fitted to the outer rap about 35mm from the front,this was when he had the coil fitted tight to the inner wall 5 holes spraying out and forward,he said it showed cleaner burn and 25c drop in temp ,that might be only relevant to the coil
All above sizes are at original size ,some will need correcting as inner cone angled.
Not sure how I would end the tubes maybe like the hobbyjet 631 combustor withe the last 15mm bent ,might be able to tell once you get it up an running on liquid and burn pattern shows up.
Your thoughts ?
p.s like the way he has the rpm reading using standard meter withe extension line and sensor fitted to front cover
|
|
reedy
Veteran Member
Joined: January 2017
Posts: 111
|
Post by reedy on Feb 1, 2017 6:37:38 GMT -5
Hi Jeff Nice finish on the plane. we call it Skip hopping ! used to get some good stuff at work till they put them all together in a compound and locked the gate, spoilsports.
The ME162 is own designed and built apart from the foam wings,not very scale or very fast, if I had used a thinner lower lift wing section it would not get off the ground. It carries 1.25 lt of fuel,no fancy electronics just a bushed ESC and a pressure switch that activates at 3/4 lb pressure and a over ride button that i hold down to start,if I let go it switches off ,if it's running and seizes up ,the pressure switch cuts the pump.
|
|
reedy
Veteran Member
Joined: January 2017
Posts: 111
|
Post by reedy on Jan 31, 2017 17:49:16 GMT -5
Hi Jeff
The GTBA has a lot of information but a lot of the early post where wrong or misleading especially with the FD3/64 and unless you read through the years you can get lead astray. you may be better withe the PT35 combustor design (which is not in the GTBA archive) as it's designed to fit a NGV like yours, let me know if you need it,but one Guy did have success with the original one you've built.
Again a bit late advice when you put walking sticks in you don,t want the large holes blowing on the sticks as it chills them,the 631 combuster sticks loop round them not an easy combustor to build the PT35 has straight sticks from the back as in the side view.nearly same hole pattern but he has altered the outer front holes and it does seem to be more consistent.
|
|
reedy
Veteran Member
Joined: January 2017
Posts: 111
|
Post by reedy on Jan 31, 2017 16:59:50 GMT -5
Hi Jeff
It's no good joining in on a thread that's been going for a long time LOL. you,ve been through most of the stuff I have been saying.(clearance and bearings) Hope I have not been too much of an annoyance,most of my posts are aimed at the silent majority,you are very near to getting it running but with temp problems,looking back at the pictures of the x1.4 fd3 with alloy compressor you need to sharpen the blades and remake the spinner larger diameter and concave, zoom in on mine in the photo.
That's an open fronted alloy compressor and a turbine with twisted blades run it to 7.5 psi cheap bearings steel race ceramic balls,I run with 5% oil in fuel (paraffin). I set the oil by running the pump for about 1 minute though the main injectors till I filled a cup 100ml with a restrictor pipe filling a small syringe to 5ml. Used a spring obtained from wren turbines for there 54 engine to preload pushing the back bearing makes it quieter takes up the slack but can move back if things expand. thrust may be about 6 - 6.5 lb just enough to take off short grass with a 10mph head wind.
As Kurt says in his book he tried a plano parallel compressor and it was very inefficient ,with a alloy m/c compressor that's nearly what you have.
I am into 90 edf foamy's at the moment, flyfly MB339,f100 super sabre, mirage 2000 built with F22,phantom,Hawk in box,s nearly got the whole squadron ! just need a F86 Sabre. They are definitely not RTF just a lump of foam in the right shape,have to carbon rod reinforce them and glass fibre the outside,the MB339 sounds just like a turbine with the wemotec evo fan and the convoluted air intakes,only get 4 1/2 min flying time, could do with a lambert turbine in then I would have the sound and smell !
|
|