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Old 10-19-2014, 01:24 PM   #1
BroncoSquid
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Default UM Heinkel He162 Salamander (Variant)

This build would be in the Oct 2014 EDF $100 Scratch Build contest if it were not for the fact I am half way around the world (Persian Gulf) and I do not have all the parts I need to complete it or the ability to fly it.

I am building a Swept wing variant of the He162 using plans and brief instructions from Model Flyer Magazine. (Aug 2013 issue) It has a wing span of 16 3/4" and uses most of the electronics from a UMX MiG-15 or UMX Habu. It is balsa construction with carbon fiber main spars. I will be covering it with dope, tissue, and paint.(3 things I don't have with me )


The plans seem to be revrese engineered from a completed model. All dimensions are in imperial measurements but when actuall measuring the plan the metric measurements are more accurate.

First issue I have, and I am looking for opinions on this, is dihedral. The instructions say build the wing on a flat surface, and the plans say "No Dihedral" right on them. But the plans show the TOP of the wing, which tapers as almost all wings do, as being perfectly flat and the bottom of the wing actually having a 3/16" dihedral to it due to the wings taper.
My guess is the draftsman of the plans isn't an aeronautical engineer, and I have NEVER seen a set of plans that showed Dihedral angles or measurements using the top of the wing as refrence. It has always been based on the bottom of the wing.
I plan on building the wing on a flat surface as it will be easier with the space I have to work with, unless anyone can give me a good reason to build it otherwise.

I'm either going to get good at flying em, or get good at fixin em!
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Old 10-19-2014, 07:22 PM   #2
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Great choice for a model! Good luck with the build. If you do get back in time to make it into the contest, I'm sure no one will have a problem including you in the contest.
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Old 10-19-2014, 09:18 PM   #3
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That'll make a nice looking ship. If possible, build the wing up side down (top down) on your flat surface. That'll put some dihedral in them. Take care, and make it back safe please.....
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Old 10-19-2014, 09:49 PM   #4
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These might help you along a little . A bubble canopy can probly be found at parkflyers plastics dirt cheap .Good luck on your build sir ! joe


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Old 10-19-2014, 11:16 PM   #5
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The swept wing version is really sharp. Should be a good flying model. Looking forward to the build.

I have a straight winged HE162 at around 20" that flies well with a foam under cambered wing. About the only issue I had was with a bit of slop in the elevator joiner, since I used a joiner with a v-tail, which is not exactly recommended. Still works fine within the amount of travel needed for flying. I had to shim the side opposite of the control horn with a few slivers of hard balsa, so that the wire could not move up or down at all which caused slop. The effect of having the elevator flaps moving a bit uneven got me into the notion that this plane could actually be controlled really well with only v-tail control, with ample wing dihedral. Before correcting the problem, you would pull up and get the tightest right hand turns ever seen. Probably better to just make a Y linkage and control both elevator flaps.

One flight the antenna wire got suck in an elevator half, where working the elevator would cause it to turn as well as climb. Almost managed to bring it back that way. It was probably something like flying with the old single channel jobs.
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Old 10-22-2014, 07:13 AM   #6
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Well, I went onto The-Blueprints.com and looked at some tech drawings of the Salamander. The drawings did show the top of the wing almost straight and a slight dihedral in the bottom of the wing from the wing's taper. However, the drawings are for the straight wing version and this one has a swept wing. For ease of building I think I will go with the flat straight bottom.

Xmech2K, I will not be back untill June, but if you extend your deadlines like CHELLIE dose......(Did he just say that???)

DEG, If I were at home and able to draw and build a symetrical wing jig, then build the wing on my workbench at home, building the wing upside down might be an option. Here at work on my desk, not so much. I don't trust myself to build the wing upside down (even if I built tabs on the ribs) there is too good of a chance to build the wing with a twist in it.

RoadKing97, Thank you for the plans. As of right now my plan for the canopy is a hollowed out balsa block. Building a small vaccuformer is on my short list of things to build when I get home. I did look at Park Flyer Plastics and did see one canopy that may work with extensive trimming.

BillG, I think the designer chose the swept wing more for the lift properties than looks. I drew a semi scale (based on fuse length) straight wing on the plans and there was a signifigant loss of wing area. If the swept wing flies well I may build a straight wing version possibly enlarging the wing to keep the wing area the same.
The elevator linkage on this particular model is a carbon fiber push rod with a wire Y at the end. I will make sure not to modify this aspect of the model.

I'm either going to get good at flying em, or get good at fixin em!
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Old 10-22-2014, 05:44 PM   #7
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It will be an interesting experiment but the conventional wisdom is that for the same span any benefits from the increased area from the sweep tend to be offset by the loss in aerodynamic efficiency resulting from the sweep - until you get to the speeds where 'compressibility' comes into play!
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Old 10-22-2014, 11:41 PM   #8
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Originally Posted by BroncoSquid View Post
Well, I went onto The-Blueprints.com and looked at some tech drawings of the Salamander. The drawings did show the top of the wing almost straight and a slight dihedral in the bottom of the wing from the wing's taper. However, the drawings are for the straight wing version and this one has a swept wing. For ease of building I think I will go with the flat straight bottom.

Xmech2K, I will not be back untill June, but if you extend your deadlines like CHELLIE dose......(Did he just say that???)

DEG, If I were at home and able to draw and build a symetrical wing jig, then build the wing on my workbench at home, building the wing upside down might be an option. Here at work on my desk, not so much. I don't trust myself to build the wing upside down (even if I built tabs on the ribs) there is too good of a chance to build the wing with a twist in it.

RoadKing97, Thank you for the plans. As of right now my plan for the canopy is a hollowed out balsa block. Building a small vaccuformer is on my short list of things to build when I get home. I did look at Park Flyer Plastics and did see one canopy that may work with extensive trimming.

BillG, I think the designer chose the swept wing more for the lift properties than looks. I drew a semi scale (based on fuse length) straight wing on the plans and there was a signifigant loss of wing area. If the swept wing flies well I may build a straight wing version possibly enlarging the wing to keep the wing area the same.
The elevator linkage on this particular model is a carbon fiber push rod with a wire Y at the end. I will make sure not to modify this aspect of the model.
Yep i made a vacume former out a electric heating plate element and a shop vac / box i built with a peg board top for making my own out of old pop bottle plastic and plastic i found at craft stores . Works good but faster if sparks has one handy and yes he did not have one for my last build either ,like what you said about to much carving and goofing around. lol Nice build tho and looking forward to your fixes on this build. joe
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Old 10-22-2014, 11:49 PM   #9
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Originally Posted by BroncoSquid View Post
BillG, I think the designer chose the swept wing more for the lift properties than looks. I drew a semi scale (based on fuse length) straight wing on the plans and there was a significant loss of wing area. If the swept wing flies well I may build a straight wing version possibly enlarging the wing to keep the wing area the same.
The elevator linkage on this particular model is a carbon fiber push rod with a wire Y at the end. I will make sure not to modify this aspect of the model.
Yeah I just think it still looks really good with the swept wings and is a beautiful model. I realize they had other reasons for it, and it probably would also have been faster than the standard version. I've spent hours at the Luft46 site looking at the German future designs and love them. I cheated on my wing area a bit with the straight wing which probably was a good thing. The converted 30mm GWS fans with Feigao motors didn't have as much power as the newer ones.

The small canopies pull well by hand, although you have to basically drop the heat gun while running and slam the plastic over the mold. The vacuum machine is on the "one of these days" list, but I'll probably never get around to it since heat pulling has worked well enough. One good thing about them is that they weigh a lot less than the thicker plastic that most of the replacement ones I've found are made from. The little HE162 was one of the easier ones to mold.


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Old 11-11-2014, 01:24 PM   #10
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The wing is 80% complete, nothing left but shaping and hinges. This being my first attempt at building with a carbon tube spar I learned alot. The build did not go as smoothly as I hoped but I am not sure what I would have changed. It seemed to be a pretty straight forward build. The instructions only call out what to make the parts out of, same information found on the plans, rather than how to put it together. There are 8 ribs per side with a hole in each for the spar. I got lucky and the small HF rat tail file I brought was perfect to have a force fit for the spar. I angled each rib on the plans and filed to make sure the spar fit nice.
Steps:
I layed down the center sheet and glued the inner most ribs (R1) to the outside edge of the sheet. I then ran the carbon tube through the ribs at the correct angle meeting in the middle with a dab of epoxy.
I then strung the rest of the ribs (R2-R7) on the tube like popcorn on a string pushing them all the way up to R1. I then glued down the LE and TE to the center sheet and R8 forming a box of sorts.
Once dry, I slid the ribs down the tube untill they were in position and trimmed the ribs to fit then glued. The holes for the ribs were not exactly 100% accurate due to being hand drilled using a file. I will have to add a bit to the bottom of a couple and sand the tops down slightly. All to be done during final shaping.
Finally, I glued on the wing tips, put down the center top sheet, and taped on the alerions.
The whole assembly felt a little "Wonky" to me. I would have prefered to lay the ribs down then add the spar but I have no idea how I would do that and keep everything straight. Maybe if I were to do it again, more of a traditional, CF reinforced top or bottom spar.

I'm either going to get good at flying em, or get good at fixin em!
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Old 11-11-2014, 05:06 PM   #11
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Good to hear of the progress. And once again, watching a build thread has taught me something. Now I know not to try a tube spar.I have to use the KISS method on my 1st project!
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Old 11-11-2014, 05:19 PM   #12
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A couple of years back I built a swept wing version of the He 162 from the remains of my original Starmax one. There is a picture of it in post Number 25 under the title 'Hobbyking He 162". Flew well until the fan exploded. The He 162 was something of an operational and aerodynamic flop, but modelling wise it was quite the adventure. I still have two of them, one brand new in box starmax, and another half built EPP version. The Luft 46 type books and online sites give some great variations on this plane, with back swept, forward swept, gull wing, V tail etc variations. Given its significance in the full scale aviation world, its surprising someone like Dynam or Durafly don't bring out a decent 70 or 90 mm EDF version. Best of luck with yours
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Old 11-11-2014, 09:17 PM   #13
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That plan might be based on Mike Stuart's freeflight Salamander: http://www.ffscale.co.uk/plans6.htm
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