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RE: Larger Revolver
Sbach For me, it is just preference. Yes, you can move a 6000# pickup truck with 4 cylinder engine, and it will move along the road, and eventually get to 55. Very 'practical'. Much better a 390hp engine. Planes fly fine with standard engines - "scale"-like. They fly better with more power. I disagree that it is a safety issue. It is the builder's responsibility to ensure that the structure will support the load. I have NEVER had an airframe pull apart due to having a larger engine. It is not that hard to beef up critical components. With a 20+ pound airframe, the R90 is asking for a 60cc at least, and the 75cc may be much better. In that regard I agree with ortho. I'm sure the R90 will get off the ground and fly sport ('scale-like') with a 30cc engine, but most of us don't fly like that. It is not just getting in the air, and flying circles; it's pushing the envelope. For those who like scale-like flying, that's great; what a great hobby! We get to make our own decisions.
Posted on: 9/17/2012 8:36 PM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11231900
RE: Larger Revolver
Mike Thanks for the details. At 19.5# (and book weights are always optimistically low - she will probably build more like the 20.5) performance will not be 'spirited' with the DLE55. My AW Ext300 weighs in at 17#15oz and is fine, but a plane 2-2.5# heavier; don't know. I have another Extra260 that is 1.5# ligher than the AW bird, and she is noticably more nimble, so another 2# in the other direction with the R90 will likely be an issue. The wing area, control surface area, cubic wing loading, etc will be interesting numbers to get. I was only half joking about the DA-60. Mintor 60 or 75 might be other good options.
Posted on: 9/17/2012 10:12 AM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11231198
RE: Larger Revolver
And the DA-60 twin for the new GRev?[:D]
Posted on: 9/16/2012 6:35 PM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11230493
RE: Larger Revolver
SBachGuy You might also check the crankcase backplate. I had an engine that would lean out and die despite LS and HS adjustments. It turned out that the backplate screws were loose, and was allowing an airleak into the crankcase - variably - so the tune would change unpredictably.
Posted on: 9/16/2012 6:19 PM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11230473
RE: Larger Revolver
Might have to get me one of those[;)] Web site is pretty sparse as to details - weight, dimensions, construction, etc.
Posted on: 9/16/2012 12:04 PM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11230123
RE: Larger Revolver
afjetmech: i have flown it with the 15x10, which was fine. The plane is perceptibly different with each pitch: 6, 8, 10, and 12. Of all of these, I like the 12 pitch the best. Only the 12 pitch prop config has been hard to get to the ground due to airspeed, but i think I can improve my skill and minimize that issue. I have, of course, sealed all the gaps to minimize the possibility of flutter, and have strong linkages from servo to control surface. I want it to go fast, but do not want to lose the plane.
Posted on: 9/16/2012 6:02 AM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11229869
RE: Larger Revolver
Guys: I got the 14x12 prop on the R70/DLE20 today. Made essentially no difference in the needles. Turning 8700 at WOT at sea level for a prop speed of about 95mph, which is the same RPM i had with the Xoar 17x6. The plane flew great. Engine spool up is definitely slower with the heavier APC prop, and thrust on taxi and takeoff is noticably less; with the 17x6 Xoar, a flip of the throttle made the plane jump forward. With the 14x12 APC, not so much. In the air, it shines! Low rate rolls are quick - probably 400-420*/sec - with the faster airframe speed. WOT low passes were quick; the plane really moved. The high pitch prop did not adversely affect her knife edges, flat spins (upright and inverted), or avalanches. I did note that she pulled more to the left on uplines but am not sure whether that is a p-factor effect accentutated by higher pitch, or just bad pilot technique on my part. Predictably, she does not pull on the uplines as strongly as with the 6 and 8 pitch props. There was almost no wind at the field today so I landed long twice, and even with a 1600rpm idle, she was carrying speed. She should settle at that rpm so i probably just need more stick time with this config. In short, i like the higher pitch props!
Posted on: 9/15/2012 3:59 PM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11229576
RE: landing bounce
Slow the plane down so that she is not flying at time of touchdown. Low idle helps. I have a four star 60 (kit), that I used to try to land at a slow flying speed -> bounced landings. With a LOW idle, so that airspeed is slower, she flares nicely to a three point. Get a really LOW idle, perhaps mixed on a switch for landing.
Posted on: 9/14/2012 3:35 PM by Author "wjcalhoun"
in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=11228686
RE: Larger Revolver
Ortho Well, the GPS does not lie! Theoretical speed at 9000 rpm with a 6 pitch prop is 4500 feet per minute, about 50 mph, so your setup must unload very nicely in the air. With that 113 on a 6 pitch, you may well have been >120 with the 10 pitch prop. I have to buy some instruments![;)]
Posted on: 9/11/2012 4:38 AM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11224784
RE: Larger Revolver
Ortho (by the way, i am an internist) Nice save. Take it for what is is worth, BUT... I do not trust clevises for anything other than toy (.40 size) airplanes [but ahicks suggestion may have merit; i never tried them]. I would use a ball link on both ends, especially since you are driving the airframe fast. I think your theoretical speed is more like 85mph, but still that is fast. I think 2-56 rod is ok if you cover it with carbon tube, and epoxy the carbon tube over the rod. Otherwise for the R70, I would use 4-40 rod. If you buy a 2-56 die and a 4-40 die at your LHS, you can cut the rods to exact length, and thread them for ball links. Alternatively, H9 makes beautiful double ended linkage rods with Left thread at one end, and Right thread at the other, so you install ball links on both ends, and can adjust them without disconnecting the linkage. They make them in sizes from about 2 1/2 to about 6 inches, in 1/2 inch increments, so you can always find one to fit. I use them exclusively on my 50cc birds. I have lost 2 different aircraft to clevises, properly installed, with fuel tubing. Ball links! Bill
Posted on: 9/10/2012 7:51 PM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11224496
RE: Larger Revolver
Don: Sounds to me as if the low end is lean - the 'die when idling' is a consequence of lean low end. Is that carb an air bleed, or a LS needle? If the engine dies when you close the throttle quickly, could be that your servo is overshooting, or that the idle is too low. Do you have a high-idle and a low-idle on a switch? If so, does it die when you close to high-idle, or low-idle?
Posted on: 9/9/2012 7:02 PM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11223223
RE: Larger Revolver
Ortho The 14x12 is my next step too. The plane is quite a bit livelier with the quicker props. Let us know how the 12 pitch works out.
Posted on: 9/9/2012 5:25 AM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11222565
RE: Larger Revolver
Markham Microdon probably has specific info, but I would be very surprised if you could NOT get a 0.95 in there without mods. The DLE20 is a bigger engine, and it fits without firewall mods. The key distance is FW->front surface of the prop drive washer, which must match the cowl. Glow engines do better sideways, rather than glow plug down, so you might have some cowl cutting on the starboard side with that engine. If you have not yet bought it, do consider the DLE20; cheaper than the 95AX to buy, cheaper to run, and better power.
Posted on: 9/8/2012 5:48 PM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11222198
RE: Larger Revolver
Guys I have to say that gasoline is really the power source of choice for this airframe. Electric, although clean and quieter, does not have the endurance of fuel, and the costs for glow fuel are minimum 6x higher than gasoline, even with a similar oz/min rate, and gasoline has a smaller oz/min rate, so the savings are even greater. Flew my R70 45 min today, on about 24 oz pump gas with Pennzoil 1:32. Less than $1 fuel cost for today. I have progressively increased the pitch. The 16x8 Xoar was great on the DLE20, but today I used an APC 15x10 for additional speed. Vertical did sag a little bit after ~300 ft upline, but she was still climbing, just more slowly, and i could hear the engine beginning to lug a bit. Landings were fine - my DLE20 has a low idle of about 1650 - so she settled nicely even with the 10 pitch prop. The responsiveness of the R70 airframe with increased airspeed is remarkable. Axial rolls are quicker, snaps are more precise, and the flat spins were perceptibly more quick (increased yaw-rotational speed) with the 10 pitch prop. Orthobird - if you can get your idle down, i think you will like the 15x10. I'm considering a 12 pitch prop, which with a top end of ~8600 rpm, would give a theoretical speed of about 90 mph, and i think the low idle will still allow her to settle. KE spins are still a bit problematic for me; she falls into either a blender, or an inverted flat spin, depending on the amount of aileron. I will occasionally get 2-3 KE rotations, but it does not lock in like the Extra 260s will do. If you have an engine that has enough power to spin up a higher pitch prop, try it!
Posted on: 9/7/2012 8:04 PM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11221359
RE: Larger Revolver
Don: DLE20; $3.70/gal [;)] Bill
Posted on: 9/6/2012 5:21 PM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11220073
RE: Larger Revolver
Ortho I hear what you are saying about the prop pitch; i might suggest that you transition to an 8 pitch first (~15x8) before going right to the 10 pitch. Unless your idle is really slow, I think a 10 pitch prop might keep the R70 flying. If your idle is 2100, your theoretical speed is about 19.5 mph - enough to keep her flying. If you can get the idle to 1600 or so, it will probably land with a 10 picth prop. Otherwise, you basically will have to fly her to the ground, and let ground friction slow her down. Try the 8 pitch first, and if it goes well, move on to the 10 pitch.
Posted on: 9/4/2012 6:12 AM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11216762
RE: Larger Revolver
Al I could not agree with you more that the semisymmetrical wing on the R70 is one of its fundamental flaws. It is a fun plane, pretty capable, but does not rate with the Extras, Slicks, and Edges for 3D and aggressive aerobatics. That is not a criticism, it is just a consequence of what GP was designing the R70 to do. One hopes that GP will bring out an 88" Revolver, and that she will have symmetrical airfoils! Bill
Posted on: 8/30/2012 7:02 PM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11212149
RE: Larger Revolver
Actually the issue of fully symmetrical wing vs asymmetrical wing is not black or white, it is a matter of degree of difference. Even a fully symmetrical wing generates lift ONLY from AOA - albeit small - generally requiring downforce from the hstab /elevators either in the form of incidence of the hstab, or slight up-trim on the elevator, assuming the CG is forward of the CL (necessary for stability). Some lift is necessary to support the weight of the plane. Hence, NO plane will be entirely free of need for trimming with various speeds. For our models, the wing loading is generally so low that the amount of trim difference between mid and WOT is either imperceptible, or we don't look for it because we are maneuvering. Agreed that semisymmetrical wings accentuate this problem due to their camber geometry, but the effect is not absent from a fully symmetrical wing. The pattern guys are all over these considerations, and there are several really informative airframe trimming guides in the pattern websites. All of them start (or restart) with the CG: change that, and you have to go through the process again. CG, elevator trim, aileron trim, rudder trim, down-thrust, and more! All trims are compromises; get your plane trimmed for hands-off S&L, and i guarantee that it will pull to the canopy in a power off vertical down line. etc, etc, etc. I, like some others, have not found that i have to retrim much in flight, perhaps because i don't do much S&L, but i have not found the extent of throttle-position related trimming to be a problem for me.
Posted on: 8/30/2012 9:49 AM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11211615
RE: Larger Revolver
Ortho More on expo, if you really want to know. JR/Spektrum calls expo 'positive', whereas to achieve the same curve in Futaba, it is 'negative'. Expo does not really delay the response of the control surface, but rather changes the relationship between stick and control surface, as microdon stated. Be careful, because differnt radios use 'positive' and 'negative' differently: - JR positive, Futaba negative expo both cause a concave-upward surface-stick response curve (which is generally what you want) So an example: With NO expo, if you move your elevator, rudder, or aileron stick 1/4 of the way over, the surface will move 1/4 of its full travel. 1/2 stick = 1/2 surface travel, etc. With expo as above, 1/4 stick may cause 1/8 surface; 1/2 stick-> 1/4 surface; 3/4 stick-> 5/8 surface; full stick, full surface. Just an example. Expo softens the response around the stick neutral point, making the plane less twitchy. It allows you to have large control surface motions, yet maintain fine control of the surface around the neutral point allowing larger stick movements than you otherwise could make. I use different expos for different total throw rates: low rates->expo about -30 (I am futaba); medium rates->expo about -50; high (3d) rates->expo -60 or -70. I also use expo on the throttle channel to linearize the throttle response which is particulary non-linear with gas engines.
Posted on: 8/26/2012 7:00 PM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11207051
RE: Larger Revolver
Did you get your new van Mike (on topic, to transport your R70)?
Posted on: 8/25/2012 5:44 AM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11205334
RE: Larger Revolver
Cool. Now you can pay forward by teaching his grandson to fly glow planes with a buddy box!
Posted on: 8/24/2012 5:54 PM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11204952
RE: Larger Revolver
I am a Futaba guy, not Spektrum, but binding is a function of the receiver, not the transmitter. Is it possible that the orange receiver has a different way (other than the bind plug) to set the receiver into bind mode? With Futaba, there is a little button on the Rx: push it with the Tx on => bind. And Mike - that van is SUCH a chick magnet! OTOH, safe transport of our aircraft IS pretty important.
Posted on: 8/22/2012 7:53 PM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11202804
RE: Larger Revolver
Guys: The final coda to the robarts hinge story: during my pre-flight inspection today, which includes pulling on every control surface and every linkage, I noted that my left aileron was loose; the two innermost hinges had pulled out from the TE of the wing. Obviously, she did not fly today. I will re-install with epoxy and be good to go. That makes 5 of 5 control surfaces originally installed with Gorilla glue having failed hinges: two ailerons, two hemi-elevators, and one rudder. It also reinforces for me the value of regular pre-flight inspection; had i not seen that aileron, i could have lost the plane. On the matter of cost of the Revolvers, i agree that the price hikes seem high. BUT, i have noted that the prices of ARFs generally are rising. I have been pricing out a new 30cc (maybe a Mintor 38 engine for it!) airframe, and for quality offerings, i am not seeing much under $400. So, for me, the R70 is still a reasonably good value, but not as good as it was at $219 (less applicable Tower discounts). Luchnia - where are you finding quality 30cc planes for $300? I see the Aeroworks, Pilot, ExtremeFlight all hovering (no pun) around $425 plus or minus. For me, value is important. I dont want a cheap airframe that will come apart in a year or two, because the costs of engine, servos, batteries, and receiver are almost always greater than the cost of the airframe, and my time in assembling is worth something. For my R70 ($220 for the plane), I have ~$650 in that other stuff. I want an airframe that is well designed, well-built, reasonably rugged (for those occasional hard landings), and looks good. At $250, the R70 is not inexpensive, but is considerably less than a properly equipped 30cc plane.
Posted on: 8/22/2012 5:38 PM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11202658
RE: Larger Revolver
Duplicate
Posted on: 8/22/2012 7:28 AM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11201976
RE: Larger Revolver
Hi Mike I will prop her with a 15x10 next time out; i don't have a Xoar in that pitch, so will have to use an APC. I was surprised with the difference in flying character. My only concern about the 10pitch prop is whether she will slow enough to settle for landing. My idle is about 1700 which translates to about 16 mph - just about flying speed for my plane. There is always the ignition kill if she wont land [&o]
Posted on: 8/22/2012 6:51 AM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11201972
RE: Larger Revolver
Guys Wow - this thread got quiet all of a sudden. I had not flown my R70 for about 5 weeks, and got to fly today on a gorgeous Texas afternoon. Blue skies, 3 knot winds, etc. I am beginning to tranform my R70 /DLE20 to more of a speed plane. I had been swinging a 17x6 Xoar prop - very good performance but slow. I switched to a 16x8 Xoar prop for today and it really changed the character of the plane. Instead of being sedate, it was spirited. Rolls were quicker with increased airspeed, and it was really much more fun to fly. I did not lose the unlimited vertical performance, although it does not punch out on a true vertical upline as quickly as with the 6-pitch prop. Flat spins, harriers, avalanches, etc were all great. For those of you with DLE20, give a 16x8 prop a try. Next time out for me, it will be a 15x10!
Posted on: 8/19/2012 8:11 PM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11199214
RE: Larger Revolver
Ortho What you describe is exactly what one would expect from a book-trimmed CG R70. Two things are in play: one is the CG, which most of us believe should be 1/2" or more AFT of the book, and 2nd is the semi-symmetrical wing which generates lift asymmetrically. At any given angle of attack (AOA) the lift vector of the wing will be more toward the 'top' of the wing than a fully symmetrical wing would be. That is, the wing takes a greater (negative) AOA (i.e. more down elevator) than a symmetrical wing would require for a given amount of lift. So even with an entirely neutral CG, an R70 trimmed for level flight upright WILL require down elevator to hold level flight while inverted. Theoretically with a symmetrical wing, and a neutral CG, the plane would not care whether it was upright or inverted (except for the down-thrust build into most engine installations). Maybe more than you wanted to know.
Posted on: 8/15/2012 6:25 AM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11194201
RE: Larger Revolver
Agree; lean is more likely than airflow (outflow). Ground tuning is only a rough guide to tuning for in-flight. Had that problem with an OS AX 1.20 in an R70. Fine on the ground, lean in the air.
Posted on: 8/10/2012 10:50 AM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11188320
RE: Larger Revolver
You guys with the R59 make me think i should get one. There is a guy at my field with an R59, and he flies it beautifully. The way his is set up and propped, it is much faster than my R70 17x6. Still waiting for GP announcement on the availabilty of the R88!
Posted on: 8/9/2012 3:09 PM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11187399
RE: Larger Revolver
Ortho Pretty bird. Mine is 9#11oz dry, so you are 1 oz ligher. Mine flies great! My guess is that if you check your dynamic CG (45* upline) that she will look nose heavy, curling quickly to the horizon, with your static cg where it is. BUT.. fly it and see; within a broad range, CG location is personal preference for flying style.
Posted on: 8/8/2012 8:10 PM by Author "wjcalhoun"
in the forum "ARF or RTF"
http://www.rcuniverse.com/forum/fb.asp?m=11186384
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