TJIRC Carbon Magnus Build (Konrad)

[Konrad]

You need to stick with balsa models where you have more control over these things.

Hank

Lol, You are correct I could build a modlie like this out of balsa.

But that's not the point. The point of a molded model is building a model with high fidelity to the airfoil. Molded models allow the manufacture of airfoils (wings) that wouldn't be practical in say balsa. TJIRC with these Magnus models is NOT producing a very good set of wings. I point to the discontinuity of the airfoil in that not only can you see the substructure but you can actually feel the spar! Also the thick trailing edge is just lazy! These issues aren't a Ferrari vs Ford thing, but rather go to the core reason why we buy molded models "Its the airfoil stupid".

Then we have the quality issues jabbing the trailing edge with a screw driver, just stupid! The gross 0.15mm deep dimples in the flap (unacceptable). It looks like these came from improper cleaning of the mold as the paint follows the dimples. Then there is what looks like a dry lay up. NONE OF THESE ARE OR SHOULD BE PRICE POINT ISSUES. We as modelers that know what we are looking at, need to inform the buying public as to what separates the moldie from the bagged balsa wing (it's the trailing edge). Also the OEMs need to know that there are folks taking note of the quality of products!

Price point issues would be like the paint finish, masking and over spray. To my eye this is fluff and has no bearing on the suitability of the model. (BTW; TJIRC is getting much better at this with each production run) Also the added accessories like the servo trays these can lead an unsuspecting modelers into a trap. For example the little tray offered for the elevator servo will not support the nose. In fact it will add a stress riser and allow the nose to fail prematurely! The wing servo trays are horrible in that they are just shy of being burned charcoal briquets. I tried to point this out to help the OEM save their laser cutter from premature failure. At this price point I wouldn't expect a carbon stab. Or high quality hardware ( I'd like OEMs to leave low grade hardware out of the accessory package).

I think Jeremy mentioned the Prodiji. The ones I've seen are fantastic ships but are shy a flap. For $650 I didn't want to engineer a second flap. At that price point I'd have gone for the dated mini "T". I actually like that the OEM for the Prodiji did NOT put any emphasis of finish. This leads me to think that what resources he had were spent on making a solid model. Love the stand way back comment from Ed(?) on the Magnus !

I choose the Magnus over the mini "T" as it looks to be an advancement in aerodynamics over the mini "T". Take a look at the wing shape. But I failed to take a look at the quality and manufacture of the Magnus that negates these modern features. The fouling of the airflow over the wings (spar bump) and those gross oversized thick trailing edges result in a wing that might as well be dragging a 12" Estes rocket parachute!


I'm thinking of just adding 200 grams of lead to each of the wing tips and just DS's this crap. There really is no point in trying to make a silk purse out of this sow's ear!


All the best,
Konrad

 

[Tahoed]

At this point, I don't understand why you keep buying these toys. If I spent as much time nit picking my purchases, I don't think I'd have the time to ever fly anything... At this point, if I were you, I wouldn't waste any more time on the build, I'd give the plane to someone who would appreciate it for what it is, or save yourself the agony of searching out flaws and just set it on the floor and smash it with a hammer..

 

[Konrad]

Because like you I love the performance of a properly manufactured slope ship.

That's just it, I'm not searching they are blatant flaws! Take my word for it, it might not show up well in the photos, but these flaws are not nit picking. For the most part they are gross flaws particularly when one knows where the true value in a molded model lies.

I post to help others and maybe even the OEM. I come from the notion that an informed customer is a happy customer. I see no value in sweeping these flaws under the table.

There is a thread here and on other forums that are basically Love Fests. I guess those are fine. But I rarely learn anything of value from them. I come from a time when the Internet was the Information Highway. Where flaws in a product could be discussed without interference from the advertisers. It was the information highway's honest disregard for the advertiser's poor products that basically killed the dead tree press. Do you place any value on the reviews you read in magazines or what is published by the staff of RCGoof's? I think not!

Please don't let my bringing to light the flaws in products diminish your enjoyment of the products, that is not my aim. Here I try to offer solutions to what I find. For example I show how to free the elevator from the the binding as a result of the overflow of epoxy across the hinge line (I also show how I messed that up). I also show how I stiffened the stab. I hope to show how I install a proper servo tray in the nose, etc.

And as perverse as it sounds I do enjoy trying to make a silk purse out of a sow's ear! Yes, there are times when the use of a hammer is the best option. But in the case of the Magnus I don't think this is the case.

Now I welcome comments from folks like you that might try to temper my position, particularly when it comes to opinions like value.

All the best,
Konrad

P.S.
I keep buying these toys as Wayne keeps providing products that have or have the potential of offering great value.

 

[Tahoed]

That's what really great about this hobby. There's an infinite number of ways to approach and enjoy it. Please take any of my comments with a smile as I really don't care how anyone approaches the hobby as long as they enjoy it. Any knowledge I gain from the "Love Fests" usually amounts to knowledge of what not to buy.

 

[Konrad]

Someday you'll have to explain how you get any value out of glowing reviews.

Unlike the reviews we see on RCGoof's written by the staff such as Jim T Graham. These are often just gross plagiarism of the companies press releases. Even more worthless when you realize that they are writing by a guy that doesn't know how to use the product he often is writing about. I actually try to use the products I write about.

Unlike those reviews I'm not trying to influence anybody's purchasing. What I am trying to do is show the "true" nature of the product. And to show how I get around the few (hopefully) issue I've noticed. I feel that this way anybody reading my threads can get the most from their hobby dollar. It is far too easy to say XYZ is junk and run away. While I will highlight any issuesI find, I also try to show how to address these issues. Now true, in the case of RCRCM it is best not to purchase the product in the first place!

All the best,
Konrad

 

[Konrad]

Now with some of the philosophy of why I post the threads I do out of the way. Let's get back to the Magnus.

I need to thank Jeremy for reminding me of this issue.

The slot in the tail for the stab is very form fitting. Because the rear of the slot is smaller that the max thickness of the stab. The stab cannot be slid into position from the rear. The stab needs to be introduced into the fuselage from the side. This can cause problems as there is likely to be a long section where the stab is rubbing against the slot. This rubbing is likely to damage the finish if not actually crush the skins as the stab is slid home.

I like to polish the part line in the slot prior to fitting the stab in the slot. I like to mask the side of the stab that might be subjected to the the rubbing. But at some point this tape will become a problem. This means that there is a risk of damage, so take your time fitting the stab to the fuselage.

All the best,
Konrad

 

[Tahoed]

You might take a minute to check the alignment at this time, as I had to do a bit of sanding for everything to square up. I replaced the JIS head screws provided with 2 mm hex heads as the provided ones are junk (as with most of the Chinese hardware these days) As for fitting the stab and cleaning up the part line, I don't think that's a manufacturing defect. I just consider this part of the "Think first and pay attention, or you'll screw something up" part of the build process.

 

[Konrad]

Agreed. What leads anyone to think I only mention manufacturing and design flaws?

This is basic test fitting prior to glueing. Along with showing the manufacturing and design flaws I try to show the proper techniques used to assemble a model properly.

Now get this I also show when I make mistakes. I also try to show how to correct these customer induced errors. At some point I need to draw the line as to how much detail one goes into. It is assumed that if at this level of modeling, one knows how to square up the flying surfaces.

I mention this fit issue as I've seen experienced modelers make this mistake. It never hurts to remind folks of this potential problem.

JIT (?) Japanese Industrial Tip. I think of these as JIS Japanese Industrial screw. (For those who don't know what these are. They are cross headed fasteners that look real close to those of a Philips head but with a bit shallower angle. There have been about a dozen cross head patents over the years).

All the best,
Konrad

P.S.
I see that even in the designer's thread Wells mentions cleaning up the part line in the stab opening.

Magnus Build thread - TJIRC

Magnus 60 inch glider from TJIRC. Prototype build ;) Hardware supplied with this Prototype: - The clevises and carbon horn were not used! I made the Elevator, aileron and flap horns. Aileron and flap horns.

forum.alofthobbies.com

 

[Tahoed]

JIS it is.

 

[Konrad]

I don't care what we call it, just as long as we all know what we are talking about (that is the crux of communication).

All the best,
Konrad