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Old Oct 25, 2011, 10:16 AM
ChuckB
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United States, CA, Santee
Joined May 2004
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Revolution

Dave,
Thanks for all the details. Your videos are great to watch and very helpful. Should pick up the depron tomorrow and start building. You did a nice job and the details are great. Thanks for all your efforts. It does seem that the Revolution is a fast flier. How does it fly inverted? Moving the servos back will help a lot for the cog. On most of my builds I find that the Rudder servo as far back as possible and the elevon servos usually about 3" from the trailing edge of the plane on deltas. I'm sure you know more about that than I do. Just a suggestion. I built a "Don't Panic" a little while back. The design is from England also. This too was a Delta plane. It was in the January 2008, Quiet & Electric Flight magazine. No matter where we might live the hobby is still the same. Thanks again for all your info. Keep us informed.
Happy Flying, ChuckB
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Old Oct 25, 2011, 12:18 PM
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Once I get the COG back "on the spot" I am sure it wll be excellent whatever way up it is..
The heart shape is hands off inverted with the correct COG, I cant see this being any different, its already showing itself just as stable..

I had another idea to move my COG.. I removed the two wheel setup, them moved the plate back, and fitted a trike setup.. this puts the main wheels behind the COG and most of the UC on the COG... It has let me remove the rear weight, leaving the battery in the same location at the front of the fin..

setup for the trike I can also add my float system that has legs...
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Old Oct 26, 2011, 05:15 AM
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Well that was a waste of time...

probably the Final flight report on the delta "Revolution" with the COG at 37.5% ...COG nearer spot on

Very dissapointing, its fine when wizzing it about and a bit nose heavy, but its slow speed handling was poor , and didnt improve when the COG was further back near the spot...and when I compare it to the heart shape there is no comparison.. The heart shape W wing is far superior fast or slow it is much better behaved..
Ive decided it will get one more chance in good conditions with the U/C off... but I dont give it much hope..

conclusion ... go heart shaped "W" wing 21" long in 3mm depron for the best results
Ive always found circular wings have better flying characteristics than deltas, Nutball and UFO, are always good..

why????...
Possibly weight...this build is near 5ozsqft over 1ozsqft heavier than the heart shape.. However, Ive never found a bit of extra weight to make that much difference, and the heart with floats was getting up to the similar wing loadings..
Likely the Shape.. circular shapes for me have always given better stability and handing than deltas... Thats not saying deltas are poor, but deltas always seem better when wizzing about, rather than at slow speed..
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Old Oct 26, 2011, 10:48 PM
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Have you consdered dropping the dihedral back down to the same as the heart? Just a thought
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Old Oct 27, 2011, 03:02 AM
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No its not that that makes it worse, It is nice and stable when flying at medium to fast, and rolls well, it just doesnt handle itself well at very slow speeds..

The rounded/circular wings have always shown me a better stablility and handling at the slow speed end of the flight range... thats the end I like, low and slow.. the nutball being my favorite, even heavy ones can be chugged around nose up very slow, my deltas get very wobbly at the same speeds..
The heart shape has the same good stability at the very slow speeds, but rolls better than my nutballs ever could, and goes better inverted...
I wont ever knock the Nutball, it is still the best RET model about..However the 4ch Heart shape has now given me a model just as good , with the ability to get practice on both thumbs, using all the channels

So my feeling is shape more than angles.. if anything the higher angles on the delta should increase the stability...
Originaly flying faster and in seriously bad winds, it was very good..
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Old Oct 27, 2011, 05:13 AM
What could possibly go wrong?
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Market Harborough
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Dave
Quote:
stablility and handling at the slow speed end of the flight range... thats the end I like, low and slow..
I wonder if the high angle of attack at slow speed has the effect of blanking the fin and reducing your yaw stability? Especially in the case where the floats are attached, you have a lot of vertical area in front of the CG.

So, maybe a bigger fin for your Delta Revolution??

Nick
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Old Oct 27, 2011, 11:47 PM
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Dave, I have a couple of flat plate deltas that simply crawl in high alpha. It is only in calm winds that I have found the round as superior in slow flight. Windy conditions and the deltas win every time in slow flight. Just my perception.

I would still try droppping the dihedral some before give up on the plane.
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Old Oct 28, 2011, 11:54 AM
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I am not giving up on it, It will get a fair trial.. Its just theres such a vast difference between that one and the much lighter heart shape..
I was flying without the floats... next time I will lose the U/C and a bit of weight..

There are a few things to try before I retire it

what weight are your flat plate deltas ? I think thats more what is making the difference for the slow flight..


Nutball or Delta... my preference has always been the nutball... even my heavy lumps... 20oz KFm4 can be flown very slowly.. almost walking speed and very stable... this one was struggling.. . Could be the fin, could be the angles, could be a mix.. little B aint it...

..
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Old Oct 29, 2011, 12:38 AM
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My biggest plane is a 20" WS delta (dekans simple delta) 8oz or so not with lots of repairs and tape. It is a bw motor 1200Kv on 3s. Flies pretty well even in 20mph winds. Maybe it is the more sweep of the simple delta, don't know but it is just a good flying thing set up slow or fast, low winds or high winds, lightweight or a pig. Maybe it is the not true delta to a point. I have seen several of your deltas too. Have you ever tried the SD? Might be something to compare to your recent designs if you haven't.
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Old Oct 29, 2011, 03:46 AM
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I will give one a go..

There still seems to be a bit of confusion so here is another drawing and the sketchup file for it..

Do please download sketchup it is an easy program and using the file you can scale with ease to what size you want.. as you do all the dimensions on the plan, whatever you have put there will be scaled.. You can then print out at full size if you want to waste paper..
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Old Nov 01, 2011, 09:55 AM
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Ive been retrying the revolution, no mods, just trying different COG locations and with and without wheels..

best COG 35-37% slightly nose heavy, only requires a slight push for inverted flight.. Further back to 40 and its flyable but feels poor..
High alpha slow flight is not good, its possible but stil doesnt compare to the heart shape which is excelent..
It is slightly improved without the wheels, but still not good..

Next to try the bigger tailfin.. ive noticed the nose rides high in the bank so it might need more vertical at the rear to improve things....
Thats the easy mod... If I decide to alter wing angles I am tempted to convert it straight to a heart shape version, then I can compare performance with weight and build differences

video.
Slow flying the revolution..problems (4 min 56 sec)
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Old Nov 01, 2011, 11:13 AM
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fin mod..lets see if this helps with yaw stability at the slow speeds..
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Old Nov 07, 2011, 09:03 PM
Build more, websurf less
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Video of the 42" W added for your viewing pleasure:

http://www.rcgroups.com/forums/showt...4#post19815375
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Old Nov 10, 2011, 05:06 AM
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I am giving up on the revolution...
Further flights of the "W" winged delta have remained poor...There is something well off with this design, it refuses to fly as slow as it should, and it wanders off track too much, even using full up the nose keeps refusing to come up... and thats with the COG back on the spot..

Ive taken some video and will process it later

The model will now have its tips cut off, that will show it.. lol...and will be modded into the heart shape..which should solve its problems

The heart shape is no problem.. I reflew it to further compare.. Its a nice and easy model, maybe not the best for high alpha hovering, but you can get the nose up to go very slow and its good and nicely stable at these slow speeds..
I increased both elevator and ailerons rates to their max .. it is obvious the W stablility is working against the roll, but with large movements it rolls easy.. with high elevator hovering is ok, although I am not so good at this maneuver... inverted its all good with only the slightest push needed for level flight .. I an running as usuall with it slightly nose heavy..
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Old Nov 11, 2011, 06:31 AM
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video .. most fliers would think this delta is ok, but for me the heart shape is a lot better.. the delta lacks in directional control at these slow speeds and is hard to get it up at high alpha.. the heart shape is fine..
.
KFm4 W wing revolutions last chance (2 min 41 sec)


and the heart shape
.
Heart shape at slow speed for comparison (2 min 40 sec)
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