Multiplex Lentus

[Hank GB Z]

I went to the RC and sport Expo today. MrMPX was there. I didn’t have the funds for a Heron or Lentus but I bought two of these mini Solius gliders. These are great little chuck gliders. Great for playing catch between two people or just throwing really hard trying to it to loop. Could be made RC but not sure it would be worth it.

Hank

Ps. Also added a pic of Kit from Knight Rider

 

[Konrad]

Jarron here has some running ailerons and elevator. Flies very well.

 

[Hank GB Z]

To me the fuse is kinda flexible. I thought it would change the trim to much and stiffing it would make it heavy. But glad to know it works.

Hank

 

[Konrad]

It pains me to say this but this will be the single most effective performance upgrade to the Multiplex Lentus! This and sanding the mold part line on the leading edge.
I tend to marry my thermals! That is once I find one I don't leave. As a result I often fly beyond MY visual range. The result is that I'm often just flying a dot. I find that a monolithic dark color gives me the best chance at seeing the ship at distance. I can't tell orientation by visual clues, rather I use the stick to tell me what the glider is doing. If the dot follows the stick I'm flying away from me. If it goes the other way it is coming towards me and I'm feeling much better!

Note that I've masked anything where glue and tape might be used. Nothing sticks to EPO foam very well. So I don't want the poor adhesion of the paint to be a structural concern! The white band at the hinge line is for the Top Models gap sealing tape. I hope you can see the blotchy paint job. To control warping, not enough paint is still too much paint!

 

[tic]

In two weeks you've just managed to paint the bottom of the wings? And I thought I was slow I think most if not all RC glider pilots would agree that a dark color on the bottom of the wings is essential for speck height flying. I also love to use "skysheeen" refective tape in various locations on the fuse and wing. It has saved a disappearing plane more than once for me but of course the stuff is useless on a cloudy day.

 

[Konrad]

In two weeks you've just managed to paint the bottom of the wings? And I thought I was slow I think most if not all RC glider pilots would agree that a dark color on the bottom of the wings is essential for speck height flying. I also love to use "skysheeen" refective tape in various locations on the fuse and wing. It has saved a disappearing plane more than once for me but of course the stuff is useless on a cloudy day.

I've been working to get my F3F fleet up to speed. But yes It takes me about a year to finish any one model.

 

[Konrad]

Spring has sprung here in the S.F. Bay Area. Yesterday I pressed my tired Samsara into action. The Lentus is to be my flat land replacement as I refinish the Samsara. What a joy it was flirting with the turkey vultures and red tail hawks. I caught 3 stellar boomers and worked a few low level thermals. Key to the low level work was the long tail of the Samsara. I fear that signaling lift might be an issue with the Lentus.

 

[Konrad]

To paraphrase Orson Welles, We will fly no plane before its time.
I'm sure I'm annoying @tic in that I've let this model age for a year.

After the paint the next thing I did was assemble the retract. While I though it was a bit dear in price and it might be, I'm impressed with the design! There are no glue joint under landing loads. Also the lift arm does not rely on a torque tube and subsequent slippage to raise the wheel.

I'm so impressed with the design that I'm thinking of getting a few more to install in some of my 3+ meter Fly Fly gliders. I know, I know this is really gold plating the trash heap!

Of note, is that I'm using an analog servo. As I fear the current draw of a stalled digital servo. I'm sorry to learn that the PowerHD 1711 is no longer being produced. This was a great replacement servo for the HS-85MG!

Not shown I've added a lot of the support rods to the Lentus, just waiting for the glue to cure. Now I am surprised that it looks like it will take more than the 1/2 oz of CA glue I bought for the model. Looks like I'll need to make another hobby shop run!

P.S.
I should note that the servo mounting legs/stand offs are not included in the Multiplex retact. They came from some "mini" Hitec servo. (The PowerHD did not supply the legs/stand offs).

 

[Konrad]

Plugging away.

I did notice a slight potential gotcha. That is the grass stiffener that goes up to the motor mount is under stress. It needs to be held down as the glue cures so as to not interfere with the motor mount bucket.

One thing that has surprised me was the call out to use hot glue on an EPO model. Normally I avoid hot glues on EPO foam as the heat tends to blister the beads causing distortion on the molded part. So far it looks like Multiplex wants mw to add hot glue to the ends of the carbon stiffeners (as load spreaders. They also want me to attach the wing surface control horns with hot glue. I assume this is because hot glue is a lot less brittle that CA. CA might fracture over time causing premature failure causing the loss of control. I had a bit of trouble with getting the horn to seat before the hot glue set. The stainless steel spreaders acted like a heat sink.

You can see that I'm starting to fit the rear bearing for the rear motor mount support. It is looking like I should have enough material to clear the canopy with only a little grinding away of the canopy lip.

 

[tic]

Nice work.. I've never used a rear bearing mount on anything I've owned but I can see where and why you'd want to.

 

[TomLaird]

Hi Konrad,
Great threat, very informative and useful. I am currently researching the Lentus kit versus the "Ready to Run" version and this has some very good information.
thank you
Tom

 

[Konrad]

Hi Konrad,
Great threat, very informative and useful. I am currently researching the Lentus kit versus the "Ready to Run" version and this has some very good information.
thank you
Tom

Thank you. I found that I needed to move the servo hood 2mm to the wing root to center the servo arm. I'm also showing that one needs to cut another connector cavity if using the Aloft supplied harness and servos.

I'm a bit reluctant to show this, but Mr Multiplex has the Lentus on sale below cost. I do link to the sale, as Aloft doesn't have any large 3meter foamies. Now if you take advantage of the sale, do look to Aloft for the components I'm using.

Quick Sale! 2/22/2023 to 2/28/2023 – Mr MPX Hobbies

 

[Konrad]

Finally glued the 2 haves of the fuselage together. I used a heavy thick bodied CA. and a lot of tape to keep the gaps closed.

I think with the addition of the rear bearing motor support I'm finished with all the fabrication. Still need to hook up the push rods and install the RX and ESC but the "building" is done.

I didn't want to place the rear bearing support directly on the EPO inner walls. So I made a smooth transition between the motor mount bucket and the walls with some spackle. I then laid up some 4 oz glass cloth to support the bucket and side walls. Per the manual Multiplex say that epoxy should not be used against the EPO so I saturated this glass cloth with thin CA.

I think the other photos as self explanatory. Oh, I did need to cut 3mm from the canopy to clear the upper support ears.

As I was reading the manual (now there's a novel idea) I read that Multiplex say the wing tip stickers are to add torsional strength to the outer tips. Well, this isn't working out too well. I don't know if it is because I painted the surfaces but the stickers aren't sticking nor are they laying down well.

Has anybody had issues with the tip decals? I'm thinking of using an iron on a low setting the stretch the decals and hopefully activate the pressure sensitive adhesive. I'm open to better ideas. These decals are the one blemish on an otherwise well designed 3 meter foamy!

 

[Hank GB Z]

Would contact cement work to hold the decals on? Also maybe MrMPX might know of a good way to put the decals on.

Hank

 

[Konrad]

This is what greeted me this morning.

I did one wing without heat and it looks like it all but lifted away from the valley of the polyhedral.

The other I used some heat to shrink and activate the glue. To my eye it looks fantastic. The technique I used was to set the covering iron on low 100 degrees C. I used a wet paper towel to buffer and protect the decals. The wet paper towel also had the secondary function of allowing me to cool down the area as soon as the iron had past.

I’ve yet to do any testing in the sun. But it looks like I need to retract my statement about the blemish Multiplex process to stiffen the tips.

 

[Wayne]

Yep - have used heat to help stickers many many times.

The other day we cut some vinyl for one of my combat wings and the vinyl would not leave the transfer tape. Drove me nuts. Brand new vinyl too! Anyhow low temp iron worked perfectly.

 

[Konrad]

I’ve just come back from flying and did the other wing. I have to say all the decals look better after I’ve run a warn iron with damp towel buffer over them.

I think this should be stated in the Multiplex manual to use low heat to set the decals. Just rubbing the decals doesn’t cut it.

 

[Konrad]

Well, I’ve hit a snag. To get the amount of travel I want in the flaps I need to use a servo arm that does not fit under the supplied hood. Heck, I can’t get the flaps to go from neutral to full down (No gap on the bottom, about 60 degrees) and stay under the hood. I like to mix my flaps as ailerons with about 2/3 the motion of the ailerons. So I need even more flap motion to go above being in profile.

Those that are flying the Lentus, what did you do about the actuation of the flaps?

 

[tic]

I just suffer with less flap travel than I'd prefer although it's plenty for a decent crow brake. I had no trouble with the wingtip stickers staying stuck w/o heat. Good tip though in case my second kit has an issue. I bought the second kit when MrMPX had them on sale for $240.

 

[Konrad]

That was a steal!!!

Maybe my stickers dried out waiting in the box for over a year.

Do you mix the flaps as ailerons?