abufletcher

This "boat" by itself, without the servos and without the final side, top, and bottom paneling (and without the 6mm balsa longerons) weighs 575g. To be honest, I wish it were less.

One "oops" moment, is I forgot to do the elevator bellcrank before varnishing the inside walls. Oops.

allanflowers

I noticed that those rear formers are very skinny (from rear view). I would assume that Chris was able to make them that way because they are ACply. In Liteply, they would have to be beefed up a lot, loosing most of any weight savings you might anticipate.
Frankly, this plane has such a large wing area I think you are going to be fine. Excess weight in the tail is another matter entirely.

TFF

The problem with the keels is they become redundant once everything else is in place, but I can see the need for them for easy construction. That is just the trade. I dont build to crash but some of it has to be built in.

CTDavies

It's a damned if you do - damned if you don't situation. Lite ply is far less scale than AC/grade ply so there was also that to consider when chosing materials. If I had gone for l/p instead, there would be some complaining that it's more difficult to stain, the edges arent nice and sharp, the surface isn't smooth like it should be etc etc, apart from it being much more fragile. Unfortunately scale models and weight issues will always be a source for lively discussions - or fortunately, depends on which way you look at it.

abufletcher

I'm not much of a fan of liteply. I'm just sort of thinking out loud, which might not be the best things to be doing on this thread.

abufletcher

Anyway, time to get back to building. After some sleeping!

ARUP

Hi- I 'purchased' a kit and plans over a year ago and have seen neither product nor reimbursement. One fella by the name of Chris Davies finally acknowleged an e-mail and asked what my PayPal account # was so he could credit my account. I seemed to have gotten suckered once but it will not happen twice! He can send a check just like I did. What gives with these clowns?

abufletcher

The CI build is on hold while Chris and I sort out some of the details. In the meantime, I might switch back over to working in the DrI...and getting the Snipe prepped for its maiden.

abufletcher

I test ran the RCV91cd for the first time since getting it back and well...it was worth the wait! What a smooth running engine!

It started right up on the first try and "stayed lit" for the full tank of gas. Being a first run, I kept the RPMs down (mid 4000's), especially since I still need to get to know the sound of this RCV engine. I also kept it pretty rich. After a few minutes I started bringing it down towards idle. 2800. No problem at all. 2500. Very solid. 2200. sweet. 1800. wow! 1600! Man, what a sound as it slowly and evenly "ticked over!" Actually, I've never before been able to appreciate the full meaning of the (somewhat British) phrase "tick over." It's so much more than just "idle!" It's like you hear each individual ignition in the cylinder, each regular as clockwork. Now, I doubt I'd actually run it at that in a model, but it's nice to know just how low it can go.

On the top end, I didn't try to get anything more than 8300 today (on the second tank). As I said I still need to get the feel for the RCV. As per their reputation the RCV does ooze a LOT of oil and it's important to consider how all that oil is going to get out of the model. But, I really am pleased with it.

Note: In the RCV91dc instructions a chart for the 14/6 prop I'm using suggests 2200-2500 for idle and 8600-9000 at the top. So I'm pretty much right there.

GianFrancesco

I am happy to read that the engine runs so well.
in my memories of a personal experience with of an old British Triumph motorcycle are many oil stains on the floor; my 90 Laser is very good, it runs well even not so low at idle, but spitting oil everywhere, I see that the saga of British engines continues .....

geezeraviation

My Feedback: (3)

Abu, ahh the British engine, I was a Land Rover/Range Rover mech/tech for 19 years, the saying was " if it's not leaking, it's empty".
Doc

abufletcher

All the more authentic, I say! Heck, If I didn't want to get my hands (or model) dirty, I'd have gone electric. [sm=spinnyeyes.gif]

What Chris and I have been discussing is a new version of the forward fuselage unit. This will slow the build down but it's better in the long run both for the kit and for future CI modelers. And of course, I get to build one of these "newer, better" fuselages as well! Too bad the parts have to travel all the way from Germany to Japan. [] Since the basic structure is well thought out and sound, the main job is to find ways to lighten it and while we're at it make some other improvements. Here are just a few sample changes.

1. More and larger lightening holes
2. A modified ply doubler shape
3. Some material changes
4. Tweaking the servo positions and access
5. Small scale improvements to the shape of the top curves on the formers near the cockpits (for example the photos show the former in front of the pilot as higher than the former between the cockpits).

We're also working on a scale modification of the cabane pylon and looking at ways to deal with the Schneider ring decking (which appears to have been hammered metal sheet on the original).

abufletcher

Note the pooled oil. It was a glorious dusk at the field as I did the engine test. Really too bad neither the Puppeteer or the Legionnaire is in flying condition.

Edit: I've connected a small fuel tank to the crankcase breather nipple so we'll see what happens during the next run. I'll see how much collects.

abufletcher

I ran the engine again today with the catch-tank (attached to the breather nipple). The small fuel tank that came with the test stand probably holds about 6oz of fuel. And I ran through two not quite full tanks, so let's say 10oz of fuel (so about 300cc). After the run, there was about 30cc (1oz) of fuel/oil in the catch-tank so a little 1 or 2oz catch-tank should do the trick on the model, maybe with some sort of "overflow" tube.

The engine ran perfectly again today between 2200 and 8600.

I do wonder though about the small flecks in the run-off oil. Would these be metal grindings? BTW, the "oil" isn't at all viscous so it's probably more like a 50-50 (or even 70-30) fuel-oil mixture.

Note: The engine instructions provide an approximate fuel consumption rate of 0.5oz per minute so with the 9oz SLEC tank the plans call for that should be more than enough air time.

abufletcher

For anyone curious about how it sounds here's a good Youtube video:

http://www.youtube.com/watch?v=NMgNm...eature=related

(Is this "our" KMOT?)

US185Damiani

Abu,

Looks like carbon or combustion byproducts.

If you take them and try to crush them up and they crush that is exactly what they are.

(learned this from years of experience in the aviation field

abufletcher

Very interesting! I tried to isolate one piece for your "crush test" but without success. So I wondered about trying a magnet. And, yes indeed, the flecks move towards the magnet! But curiously, they also seem to crush into a brownish smear. It's like being in 9th grade science class all over again!

Mein Duff

Don,
I've really enjoyed watching this models evolution and your painstaking attention to detail for the good of the greater cause. I much appreciate your dedication and sharing your projects progress.
As to the RCV engine, of which I have no experience, but being a life long 4 stroke only enthusiast, (yes I've had all those oily british engines, Royal Enfields, Triumphs, MG's, Lasers) you mentioned that you were running very rich, which is a safe bet for the first few hrs., I think this is a by-product of the rich running and soft carbon build-up around the valves, your engine hasn't been run hot enough yet for this carbon to cook & harden and "crush" as it were. I will bet that as you lean the engine out and increas revs this will burn off the remaining buildup over time, although some evidence will always be present in a 4 stroke discharge. Just my 2 cents...

abufletcher

Thanks for that input. Since the engine seems to be running just fine, I'm not really worried, just curious.

Regarding modifications to the kit, there's always a tricky balance between what's a reasonable and practical solution for inclusion in a production kit and what I might want to do on my particular model. For example, I might be wiling to hand beat metal sheeting to get a completely scale looking decking around the observers positions. But including a piece of sheet aluminum in the kit and telling the builder to "beat it yourself" is a non-starter! So we look for a compromise that looks reasonable, that's easy enough for most of builders, and that can also be reproduced efficiently and cost effectively in the kit.

Of course, my goal is not just to help CDScaleDesisgns produce a nice kit for others. I want a rockin' CI for myself too! So inevitably I'll be taking aspects of the construction places that no kit was intended to go! [sm=pirate.gif]

BTW, we just don't see enough pirate emoticons on this forum!

abufletcher

It's probably a good thing that I've paused the CI build since I really need the time to research the details of the CI. I don't know nearly as much about the details as I should. Which is funny when you consider I've been starring at the DF for at least two years! It's a case of not seeing until I need to build!

CTDavies

Ok, so Abu and I have been going through the whole 'boat' structure piece by piece to find ways of bringing the weight down. Nearly every part was tackled in some way or another so I ended up doing a new fuselage. Due to the 'cake box' construction I was able to put together both, the old one I had and a new one and compare them on my scales. The old one weighs in at 440g while the new one is 368g.
here's what I did:
F-4 was birch ply solid and has now had a number of lightening holes added. As this is the tank bay rear wall it is sheeted with 1/64th (0.4mm) ply for that watertight tank bay compartment. I could have gone for lite ply here but there are three servos mounted to it so I thought I'd stick with birch. Weight saved: 22g
F-11 is the rearmost scale cockpit former. It used to be birch and is now lite ply. Weight saved: 12g
The floors used to be solid lite ply and have also had a number of holes added. These are also sheeted with 1/64th ply for that scale look. Weight saved: 16g
Then there were multiple changes to various formers and smaller fuselage bits like the dash board etc. Weight saved 14g
The lightening holes on the fuselage rails have been made as large as I dare make them. Weight saved 16g
I couldn't compare the rails accurately as the front jacks are still on them which are now larger than they used to be. All in all I guess these changes saved about 80grammes, the weight of five CDs. Was it worth it? We'll see, but basically I ended up redoing all the milling files for the kit and a lot of the sheet drawings as well. I'm sure Abu will testify that it was a lot of work.

abufletcher

The new parts looks fantastic...and yes this was a huge amount of work for Chris. Much appreciated!!! It may not be all that much weight saved but in the process we also made a number of significant improvements particularly to the side doublers. BTW, did you take the reduced weight of the new doublers into account as well?

CTDavies

Abu, when I said fuse rails in my earlier post I meant the doublers. So 16g saved on them. I couldn't get an accurate measure on the rails now that the jack size has increased. I didn't want to break them off so maybe you can weigh just the jack when you're that far [8D] But all this means we've actuallöy saved just a tad more than 80g, which aint too bad.
Here are some pictures with the new doublers in place and also with parts of the Mercedes engine kit test shot.

abufletcher

It's well worth the effort and we CI modelers are thankful! [sm=thumbs_up.gif] BTW, the prototype dummy engine looks great!

CTDavies

Thanks, Abu. It's always good to know when I've done my daily good deed, especially when it's been for the C1 modellers around the world . Also it got me thinking about reducing weight on other models, like the DII that's been in the works for way too long now. I made myself a fuselage kit and like on the C1 checked every part to see where I could shave off some excess weight. The fuse 'boat' started of a about 360 gramms, now it is 100 gramms lighter. One thing this whole exersize did tell me, you can AutoCAD the hell out of a design, there's nothing like holding the real part in your hands. I was going to start on new thread on the DII but decided to put it here as I will only post a few things anyway. This is a taster of what I will show you tomorrow. It's getting too late again here now. ModeOne should like this. Are you watching Marc?