Trim for landing/Touch-and-Go

[Simo]

Curious what is the best-practice for trim settings when landing the Spit (and the P-51 for that matter): in case of the need for a go-around or for practicing touch-and-gos, should one actually set takeoff trim when on the approach for landing? 

 

I find the rudder trim for minimising control forces on the approach is much closer to neutral than that used for takeoff, resulting in some pretty wild yawing if reapplying power for a touch and go. Or do I just need to practice smoothly applying power and anticipating the required rudder input?

[grafspee]

In those type of aircrafts it is always rudder work most important when reducing or applying power,  especially when you goes from one extreme to another at power setting

[reece146]

I typically trim on the down wind at a steady 120-140 depending on weather (with flaps and gear down) and that becomes the trim on touchdown. I might monkey with things a little if it is a long final like when practising touch-n-goes, particularly if the mission has a larger cross wind component.

 

That said, sometimes when I feel the need to "LAND NOW!" I'll not trim much if at all and just nurse the stick and pedals to the ground as required.

 

Regarding the yawing you are experiencing, you really need to be smooth when on the front wheels and feeding in the power to get up again, particularly if your rolling speed is under ~120-140. As expected, the slower the flow of air around the rudder the less authority it has so this is where fine grained rudder control comes into play with a good pedal setup. I don't know for certain but it's always "felt" to me that under ~100-110 or so large deflections of the rudder makes the air flow around the rudder stall (partially?) so it is less effective with larger swings of the rudder than at speeds that get the tail off the ground. Curves on your pedals help here a lot I find.

 

 

HTH

[Simo]

Thanks @grafspee@reece146 for your thoughts - as I suspected, it sounds like it's a case of practice, practice, and more practice!

 

On 8/1/2021 at 3:45 PM, reece146 said:

... this is where fine grained rudder control comes into play with a good pedal setup.

My rudder setup is a cheap and cheerful Thrustmaster TFRP - just about does the job with a curve of 15 on the rudder axis, but does suffer from "sticktion" which doesn't help with the fine rudder work required for warbirds. Might try some nyogel to smooth things out as the nicer models are a big step up in price.

[grafspee]

I use cheap thrustmaster pedals as well, at landings, take offs, touch and go they work fine, ground pounding and combat this is where those pedals suck, at high speeds you need great precision, at los speeds not so much rudder deflection at high speed is tiny.

[Simo]

Yeah, accurate gunnery really requires some fine leg motor control. Not sure whether higher end pedals would help much with this TBH - I understand that rudder control IRL is more intuitive largely due to the force feedback. Unfortunately the only FFB pedal option I'm aware of is these Brunners, and not sure they are even compatible with DCS!

Edited August 3, 2021 by Simo

[reece146]

Yep, I'm using the same pedals as well with the same amount of curve, or maybe it's 20, can't remember.

 

The "sticktion" is annoying.

 

I got the kit that removes the sticktion from the throttle and it works well, helps quite a bit. It was worth doing given the price.

 

https://www.etsy.com/ca/listing/885326705/impulse-slider-mk2-thrustmaster-t16000m?transaction_id=2104522124&campaign_label=proteus_transaction_buyer_notification_boe_convo_url_treatment&email_sent=1603216657&euid=fVUtu9PR3kTMmyqNMKHNMPnB8vMs&eaid=966570422193&x_eaid=0d78dbe85a&link_clicked=4

 

I haven't researched if there is s similar mod for the pedals. For my setup I think it is more of an issue with the angles I am sitting relative to the pedals - maybe a more reclined position would help with the problem. I'm hoping to turn my attention to a "proper" simpit in the soonish future now that other projects are almost done. Then I'll see if I need to do something about the pedals. Maybe Authentikit pedals will be a thing by then.

 

 

 

 

Edited August 4, 2021 by reece146

[grafspee]

Yeah, those pedals are based on friction, so they use rails on which sliders are moving, and stiction is related to difference between static friction and dynamic friction , you can grease it but you can't remove that behavior. More expensive use different mechanism, probably based on ball bearings  which use only static friction so the  stiction is no more. And they use some kind shock absorbing mechanism which don't allow you to move them too fast.

Edited August 4, 2021 by grafspee

[Simo]

On 8/4/2021 at 6:49 AM, grafspee said:

Yeah, those pedals are based on friction, so they use rails on which sliders are moving, and stiction is related to difference between static friction and dynamic friction , you can grease it but you can't remove that behavior.

Some googling revealed this possible remedy for the Thrustmaster TFRP stiction issue on the MSFS forums. I couldn't find any of the clear Japanese-made tape in that post available locally, so I ordered a roll of this basic self-adhesive PTFE tape from Amazon and applied it to the plastic runners where they sit on the metal rails.

 

So far it has made a big difference - the stiction is greatly reduced and rudder control feels a lot smoother and more precise as a result. Not sure how long the tape will last, but £6 for a roll of tape sure beats £300+ for a pedal upgrade!

[blaster182]

Nyogel on the TFRP rails had an adverse or no effect for me. Loosening the plastic brackets of the pedals over the slide rails slightly made things better and I'm OK with the Spitfire and my helos - but there's always room for improvement: Great idea about the teflon tape, I'll try this.