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HK Specter composite glider build (Ok, assembly!)


mightypeesh
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HI folks. I have been considering this glider for a while and I quite liked the look of it for the price of 70 odd sqiddles - thanks to the lovely birthday fairy it is now on the bench!

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There is a very long thread on it over at RCGroups **LINK** which has been running since 2012!

Apparently it is a copy of something called a Passer X - but on a budget. Reading through the blog this kit is not without its problems - the main ones seem to be warped fuses, general lack of space for the gear and binding snakes and quality issues. It is however meant to be a good flyer if you can get through the angst of putting it together.... We shall see.

specter (1).jpg

The parts count is quite low, and from first look the fuse looks way out of kilter, as well as the tail feathers look a bit wonk. Wing looks alright though!

Although HK claim an auw of just under 700gms, most seem to be at the 850 plus range. the power train I have is a turnigy 28/36 motor with a 40amp esc with a 1300 3s lipo. The prop is a Cam Carb 9x7 with a 30mm spnner. servos are going to be whatever I have in my big box of bits!

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Starting weight of bare airframe parts 402gms.

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A closer look at the fuselage with a ping line shows it to be pretty straight after all.

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Its not going to win any prizes for coach building though!

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The tail plane is definatly on the wonk though...

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Looks like the scapel is coming out!

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The wings look ok at first look.

specter (8).jpg

And just a bit of a passing nod towards a servo mount.

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Ok off we go then.

specter (9).jpg

Drilled out some cooling holes in the front and reinforced the mount inside and out with epoxy.

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The motor goes straight in no problems at all. Please note the special wibbly circle of the moulding at the front. I think it must be to mach the rest of the fuse and is done for some special aerodynamic reason!

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The snakes are pre-fitted to the inside of the fuse, but must have a bend near the exit point as the inners bind badly as they go through. I just dremelled them out and will refit and fix as needed.

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There is not enough space inside the fuse to mount the sevos upright so I have made a unit up with them on to of each other to drop in the fuse.

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Even now there is only mm's of clearance not sure how I will attach the rods yet? I will overcome though!

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These sitt on two bearers epoxied into the fuse. I also added some liteply stringers under the lip of the opening - as you can see a small crack had appeared due to a moulding fault. The rest seems ok, but I will add some local reinforcement as needed.

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Quick look at the wings whilst that is drying. Mmm a whole 7mm at the widest point......

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...dropping to 4mm at the narrow end! Now I could pay £100 for a couple of ultra thin sevos that are still too thick (8mm) or work with the ones I have which are 11.5mm - tough choice!

Even moving the servo forwards in the wing will not make it fit so I will make up some blisters for them with the good old plastic bottle trick. I dont think with my standard of flying They will make much odds!

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The glass canopy is far too narrow to fit on the fuse....

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.... So into a bowl of boiling water for a few minutes and then squashed back onto the fuse until cooled...

specter (21).jpg

... Sorted smiley

That's it for now,

Cheers, Simon

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Ok folks. Not so much a build as an exercise in snagging!

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levelling up the front of the fuse with the good old 'spin it up with a bit of abrasive attached' trick.

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Do it a little bit at a time and pack with strips of paper behing the abrasive until level turn by hand before putting the power on to check it is not binding!

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That looks better.

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Made a small cable clip to hold wires out of the way of the motor.

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Snake exits reshaped and epoxied back in place

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Servo's fitted in place - the snakes sit nicely along the sides of the fuse andheld with a few more spots of epoxy.

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Tail marked for recutting

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Thats better.

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Bit of passing foam cut nice and square and with an angle of 105 to set the tail.

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Epoxied together and left to do its own thing.

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Whilst that is drying onto those wing servo's.

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taped a bit of ply onto the top of the wing to stop the servo pushing through the covering.

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Build up around servo hatch with some scrap balsa to correct height.

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tack cover and servo in place..

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I am feeling lazy so rather than carve and sand a nice blister shape to form the cover I am gong to cheat. I taped a bit of cling film over the area and used a heat gun to shrink it tight.

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Thats about the right size! Very technical mold wall.

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Not stuff everybody has sitting around the workshop (I do lifecasting as well). It is a seaweed based stuff that you mix with water and it sets in minutes.

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A few minutes later

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and some plaster of paris poured into the mold to make a buck

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...to go into my home made vacuum former. the plastic is 0.7mm PETG from fleabay.

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Sprayed from the inside with black primer and the ply servo cover epoxied in position. wrap some tape around the servo in case you need to remove it later and glue to cover. The assembly then slotos into position and is held in with a circle of Solar Trim.

It is a lot quicker than it looks - if you have all the stuff already!

Cheers, Simon

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Ok. last bit.

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Wing epoxied together and taped up. I had to wittle away at the front of the wing where it hits the locating v in the fuse to get a good fit. I then used a bit of carbon rod to make a locating post in the front.

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Tail surfaces fitted and glued in place

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I added a small fillet to the top which will be covered and popped a couple of aluminium screws in - I always did like a bit of belt and braces! Bit of filler at the front to smooth the gap between the fuse and flying surfaces.

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Squeezing it all in - not as bad as I thought it was going to be. ESC and Spektrum telemetry unit tucked under in front of the servo block...

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.... and the Rx and Vario down the back.

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Small hole drilled for the tip of the vario antenna to sit out side the fuse.

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And thats it really. I used a starting CG at 72mm and it came out absolutely spot on without any lead needed with the lipo at the front! I must say she is a good looking plane.

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AUW of 829gms. Not bad at all for a cheapy!

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An hour later down the field...... What a good looking chap. Breeze about 10 - 12 mph. perfect. Onto the important bit of how she flies.

With a launch of half throttle she had a brisk climb out to about 100 ft no problems. Cof G felt a bit forwards, so landed and moved lipo back a centimeter - What a difference! I went for a proper burn up to 150m - on full throttle it took aound 6 seconds before the altimeter buzzer kicked in to let me know I had arrived! Once again not bad considering it is a budget set up of about £20 for the motor and esc. Mooched around for a bit getting a feel for her - penetration semms good for a lightweight plane although there does not seem to be much authority in the rudder but that that may be a V-tail thing and the cg still needs a bit of twiddling. Landing is very slippery even with flaperons mixed in - she gets in ground effect and just shoots past you like a silent hovercraft!

On the last flight of the day having moved the lipo back a bit more I found a good themal straight away. Blimy, I have never had the vario constanly beeping up for that long on any plane before! From a 150m start it was not long before 200, 300, and 400m had passed. Wow! I am so impressed with this plane. I am definately what you would call a 'sport flyer' but even I had a flight of over 30 minutes from one burn of the motor and got up to 437m or over 1400ft. I only came down then because I was tired gazing at the speck in the sky. 80% left in the Lipo too!

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I you can get over the build issues with this plane it is I think stonking value for money. I have had the Radian Pro and several Pheonix 2000's as well as a Gental lady before and did not know what to expect of this. I spent maybe 10 hours over 2 1/2 days on the build - like I said - mainly problem solving, nothing too bad though.

I have decided, chuffed is what I am!

Cheers, Simon

 

Edited By mightypeesh on 28/09/2015 11:24:55

Edited By mightypeesh on 28/09/2015 11:27:39

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