Ok, outer holes it is.
On the “No I/O Thread Heartbeat” issue, it went away today so I am ready to move forward.
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I created a whole assembly for the front quad bar before installing and gluing it into the MT. In this manner, it is plug-n-play with all the connectors. Note the forward arrow on the green center tape to provide proper motor rotation for an H-frame and center the carbon bar when gluing it in place.
The slot in the main MT body was created by first cutting a “V” into the foam with a craft saw and then wrapping sand paper around on of the 12mm rod cut-off pieces until it was below the surface. This allowed me to optionally glue a thin plywood piece over the top for additional support, if needed.
Initially, I’ll use Foam Tac to glue the carbon bar to the MT frame and then determine if more support is needed. I replaced the front wheel with a short carbon rod stand to keep the MT upright.
I still plan to mount my digital air speed sensor and paint the wing tips red. Under the wings, I have long reflector strips.
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Hi Greg.
Hope I’m not to late…two things:
- your front arm needs to be moved forwards 40-50mm so it sits in front of the nose crease like on the Mozzie to get the right CoG/CoL for the quad motor setup. This is not really optional as the front motors are always loaded more on transitions. The quad arms should be equal distance from the MT CoG on the wing. Also your arms are longer then they need to be I think, and how are you going with prop clearance to the wings with the larger props? I should have realized this before, but I doubt the rear props will clear the main wing. (the front props won’t either with the current arm position on top of the fuselage) Sorry!
I’d recommend test fitting everything before proceeding. - Cutting the fuselage like that will require it to be stiffened again once you mount the quad tubes. The MT fuse is not very strong. BTW those tubes will produce nearly as much drag as the main wings. A cylinder has a Cd over 1, a wing typically around 0.1, so factor ten less. But provided your hover props clear you should be able to make it work.
Also the reason why NASA designers use free pivoting fairings on their quad arms like this to reduce drag:
Hi Sam,
The rod lengths and positions were pre-measured with the 10" props so it should work fine. When using the 10" props, there was little room for equal distance to the CG without wrecking functionality but it should be close enough. As with most VTOLs, they are designs of many compromises. The mini Talon is quite small and should handle many variances.
My goals are more hobby-based for inexpensive repeatability so the inefficiencies don’t bother me. The main efficiency has been duplicated in the forward flight power system. Keep the suggestions coming…thanks!
Yep Ok Greg fair enough.
Prop positioning and clearance is fairly important, but if it fits then no probs. 
The Hercules above looks similar to my “flying breadbox” below. The Ares V-Hawk started out as a Graupner design before it was produced at a much lower cost by Ares. It flies very well in stock form. Time will tell if I need to look into free pivoting fairings.
I appreciate all your comments and hope to see more QuadPlane threads start in the v3.8 forum.
There didn’t seem to be any reason to take the whole top hatch off to swap LiPo packs so I cut mine into two pieces so that only the section forward of the main wing bar opens up. It seemed easier two remove just one screw. This winter (our building season), I will likely replace the front screw with a hatch latch so there are no loose parts.
I also started to use my NACA Style Inlet Duct Set from Hobby King to add air flow around the rear ESCs.
Certainly more elegant than my solution. I simply used the thin foam over the rear carbon rod as a hinge. The hatch was always bending there anyways. I added some tape of course.
Thanks, Sebastian. Your 3-bladed props inspired me to change mine to the ones from HK below. I’ll still likely use the HQ 10x5 prop for the forward flight motor. The 3-blade props give the MT QP a different look. I’ll still have plenty of HQ 10x5 props to try both.
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More remarks from the side lines… 
3 Bladed quad props produce even more drag in forward flight. (if that’s what you are using it for)
If you are using that Cobra motor you listed above in your build list, you need to put a 10x8, not a a 10x5 to get maximum forward range. The pitch needs to match the thrust required to overcome drag at forward cruise velocity (ecalc can help). A 10x5 will produce more static thrust but not the right amount of dynamic thrust at cruise speeds the talon is efficient at.You don’t need static thrust for a QP, as you don’t need to launch it with the forward motor when using the quad. If there is an issue with static thrust on a QP, slowly increase the forward motor RPM to avoid prop stall.
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Hi Sam,
Thanks for keeping us efficient. Have I told you that if I fly for more than 15 minutes I get bored? 
It will be fun to test both 2-blade and 3-blade props on my MT hover rotors. Recall that my goals don’t need to be the most efficient but it is good to post more efficient solutions for others. Also, feel free to post Mozzie images here.
For the forward thrust motor, I was using the prop chart data below for my HQ 10x5 prop which is identical to the more expensive Graupner 10x5 props that I used years ago. Can you post numbers using the 10x8 prop please?
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Lol the efficiency police is in town!
Well if you get bored of flying after 15 minutes then the Mini talon QP isn’t for you!! 
We’ve had ours go 137 minutes and 115km on two 6600mAh 4S in one flight.
https://www.exmaps.com/653155
You could takeoff, send it on an auto mission, go home and have lunch, then a hour nap, then afternoon tea and still make it back in time to watch it land!
As for the prop setup the added weight on the talon increases the cruise speed (dictated by the wing loading and overall drag), so you need to have a prop pitch around +130kmh. Our 10x8 Aeronaut prop is effectively overproping it to get ideal cruise…this is by experimentation not just calculation, using that same Cobra motor. You only need around 450g of thrust at 24m/s, so provided the airframe is nearly as slippery, I’d try to stay around those sizes.
I recommend to buy a prop pitch up or down to test. The test is simple but a bit time consuming; which prop maintains a given cruise at the minimum current draw. Set it to 4-5 different speeds to test best cruise (even out of the range you’d think will work) and do that same test for all the prop pitches you have available to test. Then extrapolate the best range relative to velocity and current draw to choose the right prop. Set your cruise speed accordingly and fly longer!
Sorry, I get an itch if something’s not efficient. The German in me I suppose. 
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Wow, 2 hours and 17 minutes! I’m going to need to add some more drag.
Thanks…
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Hi Sam,
How do you make this happen? Can it be done in QSTABILIZE mode? My understanding of the Q_VFWD_GAIN feature is that it only works in QHOVER mode.
Cheers!
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That would be qloiter. It flies around fine in qloiter, and if you want to go faster just go to FBW. I only use Qstabilise for setup, tuning or recovery, and then use qloiter from then on. Generally, I try to use the wings more as they aren’t such a huge drag
I’ve been meaning to put in a request since ages for a control method change via an extra hybrid mode so that hard transitions become unnecessary all together, plus the RC input will no longer change function (in particular the throttle being currently altitude in hover and forward velocity after transition). There’s no real reason to have two flight control methods as the RC sticks can control enough dimensions without having to switch between them. The FC should do the thinking, not the pilot.
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So QLOITER can be used to hover in place, with alt. hold, but uses the forward flight motor to move forward with the pitch stick? I have typically used QSTABILIZE or QHOVER because of this information below from the Wiki. It didn’t make sense to go into FBWA mode and back out into a different mode so my transitions have been QSTABILIZE>FBWA>QSTABILIZE or QHOVER>FBWA>QHOVER.
A typical test flight would be:
- takeoff in QLOITER or QHOVER
- switch to FBWA mode and advance throttle to start flying fixed wing
- switch to QHOVER mode to go back to quad mode.
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Hi Sam
Sorry, but i believe, there are a lot of reasons. You mentioned an important issue flying VTOLs !
What control method do you propose, which is not only technical suitable for both flight modes (Copter/Heli versus Plane - I think the well known differences have good reasons) but also takes into account the habituation of our brain if we are used to fly both helis/copters and aircrafts.
With now almost 50 complete transition-flights with our tri-tiltrotor “Mozart”
we experienced that human brain automatically changes the “modes” when transition is completed.
What control method do you suggest ?
Regards Rolf
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Hi Greg (Sorry I’m replying to myself which I can’t edit for some reason)
So it depends on the conditions a bit as well and if there’s wind.
In little wind for takeoff it’s QLoiter > FBWA and back to quad with QHover first then QLoiter. The reason for that is flying fixed wing at 100kmh gives the aircraft a massive amount of inertia that Qloiter will try to brake. This is not necessary at all and is likely to result in the propulsion system failing prematurely. So switching to QHover for a few seconds, depending on your speed, slows it down before it position holds with Qloiter, which is much kinder to the airframe.
In wind only the method changes, in that we use QHover or QStabilise to takeoff or land depending on how extreme the conditions are, then once a meter or two above the ground we switch to QLoiter. The reason for this is that QHover can be a bit erratic in keeping altitude whilst in ground effect, and QLoiter trying to position hold near the ground leads to the airframe coming in contact with the ground in a uncontrolled way. There should really be a smart “Takeoff” and “Landing” mode that takes care of these common problems as well. (Another thing I should finally do something about).
So for aircraft testing purposes, like for a maiden, we like to add one control system at time. So always start in QStabilise for testing attitude control, then if everything is good try QHover at altitude to test altitude control, then QLoiter to test navigation control. This also means you should be able to recover back to a former state safely should there be an issue. (Baro blocked or in prop wash, GPS hasn’t got enough Satellites after it leaves the ground etc.) A pre-flight is strongly recommended of course
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Hi Rolf!
Maybe we should start a discussion thread to talk about QP/VTOL control alternatives instead of filling this thread with it?
Once we’ve figured it out we can then point to it for a feature request that way. BTW I’m not saying we should get rid of the current modes (yet!) rather that a VTOL specific FBW should be added, especially for new users etc. The RC itself has 4 sticks that can be used to place the aircraft in 3D space, even if only one axis is controlled by one stick at a time, instead of changing them around whilst in flight.
The critical part to “design out” of the user control, is to seamlessly automate throttle control throughout all modes of operation. Throttle control of a quad can only be achieved by the FC to maintain attitude control anyway, so adding FBWB from foward flight, seems like a logical addition for VTOLs. There would be no roll, pitch, throttle and altitude coupling in user control this way.
Primarily the control method I envisage would essentially be a FBWQ mode, where the pilot only commands the rate at which the aircraft accelerates in a certain direction using the RC sticks, and otherwise the aircraft maintains the previous state if there is no user input. For RC control this would be similar to flying a quad in qloiter, where:
- RC Pitch stick controls acceleration in direction of the aircraft longitudinal axis, so forwards and backwards. Centering the stick in hover brings the craft to a stop and QLoiter. If in forward winged flight, centering the stick will maintain the current forward airspeed, which will always be safely above the wing stall speed and this airspeed will be maintained regardless of the other RC stick inputs (climb/decent/roll/yaw), until the user actively decreases velocity with the pitch stick so that it transitions to hover flight. This RC “Pitch” stick never affects aircraft altitude however, and the aircraft will always maintain altitude determined by point 3. below.
- RC Roll stick controls acceleration in direction of the lateral axis, being sideways left and right. Centering the stick brings the aircraft back to level flight. This RC “Roll” stick never affects aircraft altitude however, and the aircraft will always maintain altitude determined by point 3. below.
- RC Throttle stick controls acceleration in the direction of the vertical axis or altitude. Centering the stick holds the current altitude, and maintains any required throttle, be it for QP hover or forward flight. This is dictated by the current aircraft flight state instead, where the airspeed determines the source of lift and can vary the throttle settings seamlessly between them to maintain the desired altitude or climb/descent rate. It does no longer vary the rate of turn using the Roll stick or the forward backward speed of the RC Pitch stick like when flying a quad.
- RC Yaw stick controls the orientation around the Yaw axis, so rotating the aircraft heading left or right. Centering the stick holds the current aircraft heading. Once again this does not change altitude, however it can be mixed in with roll control in forward winged flight, so that the aircraft uses both rudder and aileron to turn as determined by the aircraft flight state, but without necessitating user interaction.
With flight states, being either in hover or forward flight mode, this would be (is) determined by the transition airspeeds between hover and winged flight. The RC user control inputs don’t change very much with flight state, however the FC control outputs change with flight state so it uses the most effective and efficient method for aircraft flight control and managing the appropriate lift to carry out a steady aircraft state.
The beauty of this layout is that the system is not limited to just QP VTOLs but can also be used to easily fly fixed wing and is virtually identical to what people are used to with other brands of quad like DJI, except the addition of the forward flight control using the pitch stick instead. This includes belly or tailsitters as well, and can be used in ROV’s or rovers alike. (ROV could actually do with an extra 5th axis btw)
Looks like I took up the space here anyway… lol. 
Regards
Sam
PS Ideally this would become the multi axis contoller of choice: https://www.3dconnexion.eu/products/spacemouse/spacenavigator-for-notebooks.html
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Sam,
This technique looks similar to what we do in copter testing as well. My interest is more in the behavior of QLoiter. When using the pitch stick, does it use the forward flight motor to move forward? Or only use the forward flight motor to maintain position?
Thanks…
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