Hi,

For those interested I have made a web-page regarding the building of my newest pattern model, a Rhapsody Competition by Modelltechnik Lorenz in Germany.

http://f3a.rc-unionen.dk/Rhapsody_eng.htm

I hope you enjoy the page.

Hi, Mola,

I'm also building a Rhapsody.
The plane arrived in last December and is currently sitting on my working bench.
I spent a lot of time translating the German instruction into English. Thanks to the free translation web site.
This is my first 2m F3A plane and I am very impressed by the quality that Wolfgang Lorenz has provided.
By looking at your pictures I found that the firewall had been installed but I have to cut out and fix my own firewall as there is only drawings provided in my kit.
I notice that in your web page the CG of the fuel tank has been moved forward from the CG of the plane. How's that affect the overall stability of the plane in flight and what's the reason behind. You have mentioned 210 mm measured from the root of the leading edge. Do you mean the centre of the fuel tank?
I am a novice to the 2m F3A plane construction and looking forward to your valuable advice.

Thanks in advance.

LoTOM

Hi LoTOM,

Actually I made the firewall myself out of 6mm CF and Nomex sandwich material. Only drawings were included with my kit also. Also the drawings show another type of firewall than I wanted, so I made a cardboard template, and when satisfied with the fit I transferred it to the Nomex sandwich plate.


Regarding the fuel tank. The models CG is located 210mm's from the leading edge of the wing measured at the root; where the wing meets the fuselage side. This equates to 52mm's behind the rear edge of the wing tube.

You are correct that the fuel tanks CG is located forward of the models CG. I do this for the following reason: The models CG is measured with an empty fuel tank, and it's NOT a good idea that the models CG is moved backwards when you fill the fuel tank. Therefore I make sure that the fuel tanks CG is forward of the models CG.

I hope this made sense...?

By the way, the root cord of the wing is 475mm's, this means that the models CG is located approx. 44% from the leading edge.

I have attached a picture showing the location of the fuel tank on the designers Rhapsody Competition. His fuel tank is located even further forward...

Hello Morten.

I just saw a 3M 140 like yours, and i must say that the looks of it are totally awsome. Have you run yours yet, if then how does it run.

Hi, Morten,

Thanks for your advice!!!

BTW, could you share with us the method you are using to ensure the alignment of the firewall before applying glue on it. do you need some hard wood insert in the Nomex at the bolt through points or do you have any other method to avoid crashing the Nomex when tightening the nuts?

Besides, as mentioned in you wed page, the aileron servos would be embedded inside the wings. This is a very clean design and I have no doubt on it. The only problem I have is the difficulty during construction. I find it very difficult to place the servo right into the cut-out of the servo plate even though i have already made a special long screw driver. Do you have some ideas or will you switch to a surface mounted type servo?

As describes in the construction manual, the main wing locking nut sits on a plywood plate which then glued onto the outside of the carbon wing tube socket. My only worry is the strength of this set up considering the rather weak bond between the curve surface of the socket and the thin edge of the plywood plate. Do you have other setup for the wing lock?

My coach in our local club is now flying his Captain with 3M Mintor. Idle is excellent, mid-range transition is very smooth and the high end is awesome. Up line is continuous and power is endless until you throttle back. I have bought one and would also use in my new Rhapsody.

Hi,

Dan:
No, I have not run the 3M-140 yet. I have ordered the 170 now with the carbon pipe. This will go into the Rhapsody. The 140 will probably be used for the ZN-Line Synergy I have ordered...

Go here for a guy who tried both the 140 and the new 170:

http://home.online.no/~ofremmi/F3A/T..._Mintor/3m.htm


LoTom:
My firewall is reinforced with circular plywood pieces where the three mounting screws of the mount go through the firewall. In Mark Novak's thread I can see that ZN-Line uses an exoxy mixture instead, but the objective is the same, to stop the nomex from crushing when you tighten the mounting screws.

The firewall is mounted only after the nose-ring support has been installed. Then the engine is installed in the model on the mount and with the firewall installed WITHOUT gluing. When you are happy with the fit and the thrust lines I tack glue in the firewall using CA. Then I carefully remove the engine and mount. Now the firewall is permanently attached using an epoxy and microballon mixture.

I have not come to installing the wing servos yet, but I don't suspect and big problems... I will get back to this when I get that far.

Regarding the wing fixing. The plywood is not only glued to the wing tube socket, but also to the root rib where it goes through... I see no problems with this.
I'm not convinced I like his mounting system though, since it could develop sloop over time. It would probably be better to pull the wings to the fuselage either using the PL-Prod method of screws or using a rubber band and two hooks in the root ribs.

This is my first pattern model with plug in wings and I have not decided yet what to use... If any of you guys have some good advice I would love to hear it !!!

I have attached a picture of one of the PL-Prod factory models where you can see the plastic wing nuts they use to hold the wings onto the model. They have two nuts in both root ribs. The other pair are located behind the wing tube...

Thank you very much Morten. Do you think the 140 would be enough for a ZNline Enigma?

Morten,

Thanks !!

I like the PL Prod plastic nut method for fixing the main wing.

Do you know where could I buy this ?

LoTOM

Hi,

Yes, I think the 3M-140 would be nice for an Enigma. It should have comparable power to an OS-140RX. Actually I think the 3M-140 is also more than enough for the Rhapsody, but compared to the Synergy I think the Rhapsody is the most power hungry... That is the reason behind my thinking.

I actually have a Dingo in my closet which was meant for the Synergy, but I don't like the fact that you need to run 25%-30% of nitro... It's expensive stuff!!!


The wing fixing on the PL-Prod planes is done using a nylon screw in the root rib and the nylon "wing" nuts you can see on the picture in my last post. I wondered for a while where they got these nuts, which seem ideal for this purpose, until one of my friends told me that it was toilet seat hold down nuts........... I checked on my own toilet, and he was correct.


I have attached a picture showing the root rib on one of PL-Prods planes. As you can see the screws are spaced evenly on either side of the wing tube.

On your wing adjuster. It appears to be at the trailing edge. If so, wouldnt it be better at the leading edge as far as keeping your wing in true trim or does it not matter where this adjuster is located? We have found some 1/4x20 aluminum bolts that are light. It looks like you are using two hold on bolts also.

I would like to use this method on my new ship that I am building.

Wayne

Actually the picture above is not of one of my planes, but borrowed from the PL-Prod web-site... I think it's of a Tornado.

The Rhapsody has not been designed to use adjustable incidence, it only has one guidance tap on the root rib. This is made of a 10mm carbon tube.

The attached picture is of my Rhapsody, and it shows the single tap in the root cord.

I just remembered that Lorenz actually do sell adjusters for their kits... I haven't bought them, but they are available for 10 Euros.

The attached picture shows the concept.

Thanks Morten.

Hi all,

FYI, I have made a small update regarding the rudder and the rudder-horn...

http://f3a.rc-unionen.dk/Rhapsody_eng.htm

Hi,

I have made yet another update to my Rhapsody article. This time with - among other things - detalis of the 3M-170 that will be powering the Rhapsody.

http://f3a.rc-unionen.dk/Rhapsody_eng.htm

Hi Morten. What are the heights measured from the mounting plates on the 3m 140 and 170?

Dan,

I'm not sure just yet, but will check tomorrow... Anyway I took the attached picture earlier today, it should give you an idea.

Thanks Morten. Have you gotten your synergy yet?

Mola,

The fuselage and wings of my Rhapsody weights 814g and 889 g respectively. It is about 200g more than yours.

I expect the total weight would approach 4.9kg which falls to the heavy side in my opinion.

I prepare to use YS 140 DZ whcih is about 920 g in weight.

Hi,

Finally I have finished the Rhapsody article and flown the plane...

The article can be found here:

http://f3a.rc-unionen.dk/Rhapsody_eng.htm