Sebart Mini Avanti w/ K45 build thread
07-08-2015, 10:23 AM
#101
Ran one tank through the turbine last night. Fuse barely got warm :-) Plane with 2oz header tank full is 8.4 pounds. CG was easy, I did move the K45 as far forward as I could on the rails, this necessitated a slightly longer pipe from grumania, but I think it was worth it. I got to put the two batteries right on the trays and zero nose weight.
I did get a weird "pump at max voltage" warning- it didn't shut the turbine off, but it obviously delayed throttle response. Not sure if I had fully charged the pack, will have to check.
Please excuse the less than tidy wiring job, two little kids are kicking my behind, no time to make things look pretty right now!
I did get a weird "pump at max voltage" warning- it didn't shut the turbine off, but it obviously delayed throttle response. Not sure if I had fully charged the pack, will have to check.
Please excuse the less than tidy wiring job, two little kids are kicking my behind, no time to make things look pretty right now!
07-09-2015, 01:39 AM
#102
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Hi All, I am in the process of gathering the parts to install a K45 using,I think a Grummania pipe. I have a worry that the carbon stabiliser " spar " may contact the outside of the pipe ( or may even be prevented from passing through) , if there is a problem may I ask how anyone has solved it ? If my fears are unfounded I would like to be reassured !
Cheers Dambuster.
Cheers Dambuster.
07-09-2015, 05:48 AM
#103
Dambuster, The rod does touch the outside wall slightly. I ran it for a full four minutes at full throttle, (something I will most likely never do in flight) Heat was a non-issue. You could put some BVM heat shield around it to be safe. I'm using 30 oz of fuel , two dubro tanks stacked on each other.
Last edited by DrScoles; 07-09-2015 at 05:57 AM.
07-09-2015, 10:38 AM
#104
My Feedback: (19)
Dambuster, The rod does touch the outside wall slightly. I ran it for a full four minutes at full throttle, (something I will most likely never do in flight) Heat was a non-issue. You could put some BVM heat shield around it to be safe. I'm using 30 oz of fuel , two dubro tanks stacked on each other.
07-09-2015, 03:25 PM
#105
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Hi Dr Scoles, Thank you for your prompt reply...and VERY reassuring too ! From your previous posts I know you are currently "time poor" so your reply is doubly appreciated. Can't wait for your flight report......no pressure !!!
Thanks again,Dambuster.
Thanks again,Dambuster.
07-09-2015, 11:41 PM
#106
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John
07-10-2015, 06:48 AM
#107
thanks John. People have got me so freaked out about the weight, I went with what I thought would be a 5 min flight. You could easily put two 20oz tanks here… We'll see how it goes. The plane is ready, we're gonna try to go next weekend. :-)
07-11-2015, 04:33 PM
#108
She is one sweet flyer, your gonna love her. Can't wait to get some more stick time on mine.
Actually went ahead and booked one more kit.
I believe V3 retracts are coming soon, but more expensive.
Chatty.
Actually went ahead and booked one more kit.
I believe V3 retracts are coming soon, but more expensive.
Chatty.
07-12-2015, 06:13 AM
#109
Xcghxgj... Check out post #83 on this thread... Gary with sr#001 has already maiden his jet and loves it... Also re verify your serial # I don't believe you have #005
08-11-2015, 11:24 PM
#112
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Hi Dr Scoles,
Been reading your Thread on your build as I have been building the same and just done. Hoping to fly her soon but need to find a gap with good weather as it's windy month for us here in South Africa. How did you maiden go? Also wanted to ask you about your tail pipe.
I got a pipe after hunting around from a dealer locally as they not readily available locally, I did a start this weekend and found that the tail section of the fuse got pretty hot. I thought it may be that I was using a single wall pipe but I see you using the same and I would imagine stainless steel would heat up all the same.
I have since the weekend gone and got some ceramic heat insulation as well as aluminium heat insulation and finished the tail section last night using both (two layers) and silicon for applying. It worked out well as I found my nose section was a little heavy as I did a bit of customising on the tray to fit my 12 channel spectrum receiver as well as the spectrum telemetry setup. I wanted this to monitor 3 vitals:
1. Temp sensor in cabin
2. Voltage sensor for ECU battery
3. Air speed sensor with pitot tube mounted in nose (This is to test fly her and see her stall speed so I can program warning into radio for stall)
The all out weight fully fuelled is around 4.7kg's
I am using a 709cc main tank and a 120cc hopper as an air trap. Based on full throttle rating of the turbine it should give me around 5.3 min total time but I planned on 4 min to land. We also high up at 5500ft so air being thin our stuff tends to fly faster with less throttle anyway so should get more time.
Did you do any insulation in yours and please let me know how she flew. I unfortunately am not able to get brakes for her here as nobody has any stock locally and importing a set takes forever due to our poor postal system.
I do also have the 90EDF version which I have flown twice and she lands fine at our altitude with half flaps and stops in about 50-60m so the heavier turbine version would imagine could stop in about 80-100m without brakes?
Our runway is about 150m long so it should be ok but would like to hear how yours went. On the EDF version I did a stall test and she barley stalls flat on her belly (tail down) and my guess was at about 25km - 30km stall speed. The EDF version weighs in at 3.7kg so stall speed would be a little lower so imagine turbine would be around 40 - 50km?
Anyway will also post some of my build pics shortly.
Cheers
Been reading your Thread on your build as I have been building the same and just done. Hoping to fly her soon but need to find a gap with good weather as it's windy month for us here in South Africa. How did you maiden go? Also wanted to ask you about your tail pipe.
I got a pipe after hunting around from a dealer locally as they not readily available locally, I did a start this weekend and found that the tail section of the fuse got pretty hot. I thought it may be that I was using a single wall pipe but I see you using the same and I would imagine stainless steel would heat up all the same.
I have since the weekend gone and got some ceramic heat insulation as well as aluminium heat insulation and finished the tail section last night using both (two layers) and silicon for applying. It worked out well as I found my nose section was a little heavy as I did a bit of customising on the tray to fit my 12 channel spectrum receiver as well as the spectrum telemetry setup. I wanted this to monitor 3 vitals:
1. Temp sensor in cabin
2. Voltage sensor for ECU battery
3. Air speed sensor with pitot tube mounted in nose (This is to test fly her and see her stall speed so I can program warning into radio for stall)
The all out weight fully fuelled is around 4.7kg's
I am using a 709cc main tank and a 120cc hopper as an air trap. Based on full throttle rating of the turbine it should give me around 5.3 min total time but I planned on 4 min to land. We also high up at 5500ft so air being thin our stuff tends to fly faster with less throttle anyway so should get more time.
Did you do any insulation in yours and please let me know how she flew. I unfortunately am not able to get brakes for her here as nobody has any stock locally and importing a set takes forever due to our poor postal system.
I do also have the 90EDF version which I have flown twice and she lands fine at our altitude with half flaps and stops in about 50-60m so the heavier turbine version would imagine could stop in about 80-100m without brakes?
Our runway is about 150m long so it should be ok but would like to hear how yours went. On the EDF version I did a stall test and she barley stalls flat on her belly (tail down) and my guess was at about 25km - 30km stall speed. The EDF version weighs in at 3.7kg so stall speed would be a little lower so imagine turbine would be around 40 - 50km?
Anyway will also post some of my build pics shortly.
Cheers
08-16-2015, 07:10 AM
#113
Hi Madiba, my pipe is not single wall. It's got two. The fuse barely gets warm. Not sure if it will be a problem with the single wall or not. Mine still hasn't flown, the move that took an eternity is in full swing, almost done though. Our big jet event is at the end of the month, I will fly it then...finally!
08-17-2015, 01:02 PM
#115
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Hello. My avanti is already at home but waiting for a wren44. I would like to ask the guys that are installing a k45 if you are replacing the paper hinges, I am putting kavan hinges and they look very strong, some dremmel is needed but I don not want to forget a detail since the plane will be over powered. Are you keeping the paper hinges? Do not you expect possible issues by keeping them?
http://www.kavanrc.com/IndexText/0129E.html
I am also waiting for the HK electric brakes 2" wheels. Will let you know how it goes, the are cheap.
just got the pipe from grumania, same that drscoles but for wren44, grumania just released this pipe two weeks ago. It is also double wall.
Thans
http://www.kavanrc.com/IndexText/0129E.html
I am also waiting for the HK electric brakes 2" wheels. Will let you know how it goes, the are cheap.
just got the pipe from grumania, same that drscoles but for wren44, grumania just released this pipe two weeks ago. It is also double wall.
Thans
08-17-2015, 01:21 PM
#116
Hello Ramon,
The paper hinges should work just fine, I had them on a boomerang Élan, which was powered by a 28 thrust turbine, and after 300+ flights it holds up just fine.
Use thin cyano to glue the hinges, quite sure if you try pulling them out, you would damage the control surface too.
Chatty.
The paper hinges should work just fine, I had them on a boomerang Élan, which was powered by a 28 thrust turbine, and after 300+ flights it holds up just fine.
Use thin cyano to glue the hinges, quite sure if you try pulling them out, you would damage the control surface too.
Chatty.
08-18-2015, 01:33 PM
#119
Not yet, it's peak monsoon here in India, have had just 3 flights on the Avanti so far, all on Tarmac.
Others on RCG have been having some problems with the trailing struts, retracts seem fine for most so far.
The ER 30s are bigger in size, than the stock retracts, and a bit heavy for this frame I think.
Chatty.
08-18-2015, 01:57 PM
#120
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Thanks cmakhija, I will instal the paper hinges then, in fact my local dealer told me today that they should hold fine the extra power. This is my firs real turbine jet and of course I am afraid of missing something. Thanks for your help.
08-24-2015, 07:05 AM
#121
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Hi,
Did Maiden yesterday, still using stock retracts with stock struts but installed Tam's smaller wheels with brakes for HABU32 as that is all I had or a 50mm heavier wheel. K4.5 has plenty of power and took off with 50% throttle and take off flaps settings. climb out was gentle and gradual and then went into cruise rates (normal rates). Minimal trim was needed (elevator up 2 clicks) and she flew beautifully. Then tried stall with full flap setting and very similar to EDF version she slows down very nicely and does not drop wing.
Did low pass at 50% throttle and she flew by stable and quick and found I needed to back off throttle pretty quickly almost to 25% throttle as she ate up the sky pretty quickly. Mine weighed in at just over 5kg's with all the extras, 820ml fuel incl hopper, telemetry (pitot tube, temp and voltage) , dual batteries on my spectrum AR12120 rec, 2100 life 3s pack , electronic brake valve and cylinder. She slowed down nicely but one big problem is the stock nose strut has a screw that hold the nose wheel collar on and that pops out very easily.
On landing it gave way and the nose wheel folded back resulting in a sparks flying aluminium grinding landing. Still had approx. 4 OZ of fuel in main tank and hopper was full. Flew for around 4 min. Pro could get more with a more conservative flight once I get more comfortable with her.
One problem I seem to have is the clunk in the main tank does not seem to follow the gravitational pull quickly enough and so it sucks in air into the hopper tank. I tried changing from Tygon to black smoke piping which is softer but still the same. Going to shorten pickup line and got a heavier clunk today.
Got replacement strut (still Sebart) for now to fly her again tom or Wed and waiting for my Tamjets set to arrive but otherwise so far a great flyer.
Take off distance approx. 70m and landing with brakes about the same at 5500ft altitude.
Did Maiden yesterday, still using stock retracts with stock struts but installed Tam's smaller wheels with brakes for HABU32 as that is all I had or a 50mm heavier wheel. K4.5 has plenty of power and took off with 50% throttle and take off flaps settings. climb out was gentle and gradual and then went into cruise rates (normal rates). Minimal trim was needed (elevator up 2 clicks) and she flew beautifully. Then tried stall with full flap setting and very similar to EDF version she slows down very nicely and does not drop wing.
Did low pass at 50% throttle and she flew by stable and quick and found I needed to back off throttle pretty quickly almost to 25% throttle as she ate up the sky pretty quickly. Mine weighed in at just over 5kg's with all the extras, 820ml fuel incl hopper, telemetry (pitot tube, temp and voltage) , dual batteries on my spectrum AR12120 rec, 2100 life 3s pack , electronic brake valve and cylinder. She slowed down nicely but one big problem is the stock nose strut has a screw that hold the nose wheel collar on and that pops out very easily.
On landing it gave way and the nose wheel folded back resulting in a sparks flying aluminium grinding landing. Still had approx. 4 OZ of fuel in main tank and hopper was full. Flew for around 4 min. Pro could get more with a more conservative flight once I get more comfortable with her.
One problem I seem to have is the clunk in the main tank does not seem to follow the gravitational pull quickly enough and so it sucks in air into the hopper tank. I tried changing from Tygon to black smoke piping which is softer but still the same. Going to shorten pickup line and got a heavier clunk today.
Got replacement strut (still Sebart) for now to fly her again tom or Wed and waiting for my Tamjets set to arrive but otherwise so far a great flyer.
Take off distance approx. 70m and landing with brakes about the same at 5500ft altitude.
08-25-2015, 06:12 AM
#125
I've been asked to post the final CG and throws here for anyone looking to find them. When I built this jet, there was no manual yet, but our testing found the perfect CG to be 145mm, this is exactly half way between Seba's now recommended 140mm (intermediate) to 150mm (high acrobatics) recommendation. I will post throws below once I double-check...
Low, Medium, High
Ailerons: 5/8", 3/4", 1"
Elevators: 1/2", 3/4", 1"
Rudder: 7/8", 1 1/8", 1 3/8"
Flaps: 7/8" (takeoff), 1 1/2" (landing)
Low, Medium, High
Ailerons: 5/8", 3/4", 1"
Elevators: 1/2", 3/4", 1"
Rudder: 7/8", 1 1/8", 1 3/8"
Flaps: 7/8" (takeoff), 1 1/2" (landing)