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| Giant Scale Aircraft Discuss Giant RC Scale Aircraft. |
Topic Review (Newest First)
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| 12-22-2015 12:30 AM | ||
| orthobird |
Re: Dalton Extra 300 ML build I am building one now, that is purely stock, per plans, except, I reinforced the wings with carbon fiber. Should be interesting to see what she weighs once done. the 1/4" square carbon fiber rods are 48" long, and they lock into the plywood of the root cap, and into the balsa of the wing phenolic support. It is glued in with West Epoxy resin, slow set, and a total of two per wing, one on top and one on bottom. This addition to each wing adds an additional 3 ounces per wing. I let you know how it goes. Have a good night. |
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| 12-22-2015 12:26 AM | ||
| Trumpetman |
Re: Dalton Extra 300 ML build Hi Orthobird, no need to apologize about a question! I was not offended at all with the replies to the thread that it triggered from MEL and Tony Russo. In fact I was pretty tickled that they took the time to fill me in on the reasoning behind the design. I'm thinking about building one stock to see what I'm missing (that is if Tony will sell me one LOL). Sorry to hear about the problems you had with yours. Mine has had a couple of minor dings but overall has held up really well. |
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| 12-21-2015 11:45 PM | ||
| orthobird |
Re: Dalton Extra 300 ML build I missed all of this, and was just back to read this. I am sorry, I am partly to blame, as I asked the question to Gordon. It was my airplane that weighed 45 pounds. I can explain why. It being the first Dalton I built, and the first kit I built that was a 40% sized airplane. Having no experience in building an airplane this big, I was thinking of all the forces that could be applied to it, so it is super reinforced. For example, the cross bracing, the plans call for one on the top and one on the bottom, going in opposite directions. Well, I built mine with double cross bracing, two on top and two on bottom, this was in the shape of an X, instead of a \ or a / I probably used more glue than most, and it just ended up being heavy, (I am using canisters and a DA 200 ML.). It is quite cool that ML came over here to this forum to chime in!! that is way too cool!!!! Gordon has definitely written and posted an excellent build thread, which I use as a guide. He has awesome tips. OK, here is my update, it is still heavy, and after having been in a bit of an accident, the airplane was rebuilt, and it is still same weight as before, but now it has a different scheme. Mine has Incidence set at zero/zero, And I do have a down line mix of about 1%. For this whole year, I flew sportsman, and my airplane was in 8 competitions, unfortunately, on the last competition, in Sherman, Texas, on the friday of the weekend competition, while i was practicing, on the 4th flight of the day, I was coming into land her, and I was about 50 yards away from being in line with the run way, and my airplane landed in a tree. In any event, I built a Dalton Yak, and I realized how much nicer it flew than the Extra 300, and then I discovered why, after reading Goldman's recommendations on trimming an RC airplane. Turns out, my Dalton Extra 300 ML, whole season long, i was flying it just a tad bit too nose heavy. And this was the problem I was having trying to do a spin entry (Stall), it always looked like I mushed it in, and at Clover Creek, I got like 8 zeros!!! In any event, the new Dalton 300 ML (new in that, it has a new life, but it is still the same old one), flies real great!!! I intentionally made it just a tad bit tail heavy relative to where it was before. one of Gordon's friends posted, several posts back, maybe my CG. But i had not read this til now. Wish I had seen this back in April!! Oh well. |
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| 04-17-2015 06:41 PM | ||
| Trumpetman |
Re: Dalton Extra 300 ML build Hi Mark, that is a lot of information to digest!! Lots to think about and try this year. Your questions: (my answers in red) 1. What are you basing .75 degrees positive off of? I.E. What is your baseline? The wing (and stab.) incidence was measured from the top of the fuselage (the flat area beneath the canopy) 2. What are you measuring this with? digital level 3. How many different times over the course of the airplanes life has this been measured? when it was first set up (2 years ago) 4. What, if any minute warping moments do the trailing edge of the wing have? The wing incidence is held by the steel locating dowel in the trailing edge of the wing root that slots into an 1/8 " plywood plate on the inside of the fuselage. This has started to show some slop and was on the list of items to address this spring. 5. Can you post pictures of the shape of the wing at the tip and the stab at the tip, roughly the last 30%? I've attached pictures of the wing and stab tips. It is a bit difficult to see in the pictures but they are essentially squared off with just the slightest radius on the edge. A few other modifications that I made while building were "shorty" ailerons, straight hinge line for the rudder and stabs (as per the approach that Kurt Koelling has taken with his Carden Pro) as well as building a shelf back from the stock fuel tank tray to get the fuel tanks sitting almost over the CG. I'm using one servo per aileron surface (Hitec M7990TH - just over 600 oz/in. torque) |
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| 04-17-2015 07:48 AM | ||
| LEE |
Re: Dalton Extra 300 ML build Good comments from Leesburg. I agree with everything except the muffler part. Open stack mufflers in today's environment just doesn't cut it. Noise is such an issue everywhere that I think canisters or muffled tuned exhaust should be mandatory. The weight can be offset by placing the tank high on the fuselage and preferably near the CG as is done on the Carden PRO. I like the talk about comparisons to FAI pattern planes. I agree that we are looking at a whole different set of parameters and flying routines and each are unique. I look at what the top pilots are doing and copy them so for my PRO its 0-0-0-and three degrees of right thrust. I am also at the same CG and very similar throws as Kurt Koelling ( and others) so now it's basically burn lots of fuel and go to as many contests as possible which is where you really learn a lot. Good stuff! |
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| 04-16-2015 07:28 PM | ||
| -Rick- |
Re: Dalton Extra 300 ML build Quote:
Could I ask what size screws you used to mount the gear with the hardwood rails? I would like to do the same and get rid of the blind nuts. Thanks, Rick P.S. Really enjoying Marks reply's! I always did wounder about the weight of a plane for IMAC. I always believed a heavier plane (slightly heavier) would hold a line better but in his reply's about a heavier plane having more of problem with downlines makes perfect sense. Always so much to learn!!! |
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| 04-16-2015 09:56 AM | ||
| Scrappy |
Re: Dalton Extra 300 ML build Awesome updates on this thread!!! Very cool of Mark to chime in, makes for some great reading!!! 
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| 04-16-2015 06:17 AM | ||
| Mleseberg300 |
Re: Dalton Extra 300 ML build Trumpetman, The honor is mine. Experimenting is excellent. I encourage it. Questions 1. What are you basing .75 degrees positive off of? I.E. What is your baseline? 2. What are you measuring this with? 3. How many different times over the course of the airplanes life has this been measured? 4. What, if any minute warping moments do the trailing edge of the wing have? 5. Can you post pictures of the shape of the wing at the tip and the stab at the tip, roughly the last 30%? 0-0-0 and -3 = 0 degrees up/down engine thrust vector, 0 wing based on how you wish the model to track in level flight (I.E. Straight down the center of the uncompensated right thrust crank moment) which is relative and slightly different over time to the canopy rail, 0 or identical incidence on the stab (relative to the wing), and 3 degrees right thrust vector. I haven't seen my interview but the intention was to inform that the airplane was "like" an F3A machine in flight, but in no way the same from a working aerodynamic standpoint or what we did to achieve that. Now, I have spent the last 30 minutes looking over my programming numbers for the last 10+ years of all my competition IMAC airframes including 35% airframes. The list includes in the following picture attachments, some of the aircraft: Now, A few observations: 1. The lighter and more neutral the Extra 300, the less sideslip compensation needed, the less downline mix required due to the simple fact that the airplane isn’t changing Q or (velocity) as fast in a given distance, but the penalty is a smaller “grooving" speed range and slightly decreased tracking on a given line. 45 lines improve but the speed range to track that line is smaller. Also, rolling circles suffer in 1/8 high sideslip increment situations. All of my Extra airframes, given enough time, will want to pull to the canopy on a downline. A lighter airplane doesn’t penetrate gusty wind conditions as well as a higher equally mass distributed airplane. So, cementing a led weight in a single compartment doesn’t have the same “ride” effect. Just ask B757 pilots who have flown 727’s. a.) to combat this there are two options. 1. Slow the airframe down. I.E. more diameter, less pitch. 2. Lighten and make the airframe more neutral. I.E. more tail heavy 2. The more nose heavy the Extra, the better the tracking in vertical uplines but pay the penalty for learning the downline mix. Maybe a switch is right for you. The grooving speed range is very much amplified in the pilots favor, not exponentially but linear to a certain point. a.) to combat this 1. Burn gas 2. Consider a way to slow the model on a downline. VPP only a couple degrees would be an awesome fix, but the weight penalty is prohibitive. Unless you know a guy who knows a guy who can make a constant speed system that works. So, pitch and diameter it is for now. 3. A proper vertical center of gravity with respect to aerodynamic center should meet behind and close to the longitudinal CG. a.) To take advantage of this, use stock mufflers or determine a way to offset pipe weight vertically. This is really important as the aircraft slows for Hammerheads and low speed figures. A lot of weight in any 40% model down low is a bad thing for suitable competition characteristics. Please refer to my Clover Creek Classic Programs vs. Tucson 2012. It is very easy to see during certain maneuvers. 4. The only awesome round cowl airframe to come close to the Extra’s compromised flight characteristics was the 102 QQ Yak 54 at 24lbs but it had a pull pull rudder so that pissed me off. Gernot’s Yak 55 was awesome at some things but the workload was unacceptable in others. Now he flies an Extra like us all. The one exception for me was his wood wing Yak that never came to the states but he let me fly it a number of times in Europe. A very very fun model at 36lbs with a DA200L. No downline mix on this bird. Want to guess why? It never got above walking speed in a downline. 5. Trim changes with Indicated Airspeed (IAS), MACH Number and CG, so get over the fact that a model will never be great at everything but could possibly be fantastically good at a number of things. All of these change thousands of times in the course of one flight. If you know whats going on, you know that repeating these changes accurately and continuously is vital to a good flying airplane. 6. Please understand the difference between Indicated Airspeed and Groundspeed. Its really easy to trust but hard to trust by feel alone for most. Just because the model is coming straight up and straight down doesn’t mean IAS and TAS aren’t still very real with regard to trim changes. 7. Wood Airframes change a lot over time. A LOT! Continue the trimming chart always and regularly. One busted stringer on the fuse could mean the difference between an axial roll and a no mans land of guessing! It’s 4:58am and thats all I can muster for now. Hope it helps, ML |
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| 04-16-2015 02:33 AM | ||
| Trumpetman |
Re: Dalton Extra 300 ML build Hi Mark, I am honored to have you guys jump in and describe how and why the Dalton ML Extra was designed the way it was! I built my plane with the ability to adjust the incidence on the wing and the stab because I wanted to experiment. I've been flying it with about .75 of a degree positive wing incidence and 0 degrees on the stab. The plane feels great for me and the level that I fly (Intermediate). That said, I'm certainly not suggesting that there is any kind of problem with the design that you and Tony have arrived at. Like I said, I just wanted to experiment. I'm not sure where the figure of 45 pounds came into the discussion since my plane weighs in at about 41.5 pounds with a DA200L. BTW, I've always thought of this design as being like a big F3A plane because you yourself described it like this on one of the TAS DVD's that I have  Given what you have said though, I'm going to reset the incidence on the wing back to 0 and retrim the plane for this season. Question: Your plane is set up at "0-0-0 and -3". What is the -3 referring to? Engine down thrust? I'll have to double check my plans again but did Tony build downthrust into the firewall design? |
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| 04-14-2015 11:12 PM | ||
| Mleseberg300 |
Re: Dalton Extra 300 ML build Please, and with respect changing the incidence of the wing will do nothing for the overall compromise of the design. 3-5 clicks of up elevator trim is absolutely normal. I will explain myself, but it will take three pages of typing and a lot of theory comprised of exempts from Mario Somenzini, QQ, Bob Godfrey, Jeff Boerboon, Von, and George Hicks. Plain and simple, this is not an F3A machine. F3A Theory does not apply in any shape or form. The Re numbers are different, the wing loading is different, airspeed dissipation is different, three different center of gravity points are different, AOA and Sideslip excerpts are exceedingly different, Aerodynamic centers and mass distribution is different. This airplane is the culmination of 13 different variations of the Extra 300 series aircraft with over 1400 hrs flying the full scale Extra as a base line and 20+ model variations from 1994. I'm not here to tell you not to try something on an airplane that you purchased, simply to inform you that it has already been done before. This Extra is by its simple nature the best compromise design. I had a chance to fly the full scale MXS R last weekend. I know why now Rob chooses it, but there is a reason the 330SC is WC in the classic program. Only one person could ever win the WC in the MXS. There are more than a handful that could do it in the 330. 45Lbs is way too heavy and I like a heavy airplane. What is the flying weight with fuel? I have had airplanes ranging from 39.6 to 43 lbs. All with DA200, DA200ML, and DA200L. 41.5 lbs with 3 very specific CG points and the DA 200L are the best for me and flying in the desert. KE Mix numbers and downline mix number decrease with aircraft weight and CG change. They also decrease by going to the single place canopy. You absolutely must separate F3A and IMAC. It is very disturbing for folks to make these types of changes then come to me and wonder why their aircraft is so far out of trim that they cannot rectify it, sell the airplane and the next guy ends up with the same issue and worse. Its happened on a number of occasions. All because a gentleman had a theory with good intentions. Tony and I have already made the mistakes for you. This is what the airplane was designed for: The desert in 20+ mph winds Higher Stalling speeds Higher overall flight speeds Minimal Aileron differential and twist distribution Minimal Fuse twist Wheel Pants DA200L Direct drive Rudder.........NO PULL PULL Period 41lbs NO Tuned pipes or Canisters Straight Mufflers Minimum Sideslip 0-0-0-and -3 All this equals success with this particular design. Any variation is an unknown and no longer the best compromise in my opinion. BTW, you should argue your point of view otherwise you might not fully understand all sides and make an educated determination. Its a lot of money to invest and we want you to get the best model possible. Hope this helps Mark Leseberg |
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